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This page contains information regarding Star Trek: Discovery, and thus may contain spoilers.

For the mirror universe counterpart, please see Sylvia Tilly (mirror).
"Did you ever think, when you signed up for Starfleet, that you'd be forced to see war and death?"
"Death found me when I was a child, so, yeah, I knew what I was getting into.
"I don't think I did, not really. Does that make me naive?"
"It makes you optimistic.

Sylvia Tilly was an ambitious female Human Starfleet officer who lived during the mid-23rd century. She served aboard the USS Discovery while still a cadet in 2256, later commissioned as an ensign. After traveling to the 32nd century, Tilly became an instructor at Starfleet Academy, a position that she held for decades, eventually becoming the Academy's longest tenured instructor.

Early life[]

Tilly was born in 2233 on Earth. (DIS: "New Eden", "An Obol for Charon", "All Is Possible") She was raised by her mother Siobhan, a member of the Federation Diplomatic Corps, whom Tilly described as a "hardass" who refused to compromise, and whose presence was infrequent during Tilly's childhood. Siobhan had planned for her daughter to join the Diplomatic Corps as well, but Tilly ultimately chose to join Starfleet instead. (ST: "Runaway"; DIS: "The Red Angel", "All Is Possible")

Tilly's year of birth was not stated outright, but can be concluded from the fact that she was fourteen in 2247. Likewise, her mother's name has not yet been stated on screen, but comes from closed captioning.

In 2242, when Tilly was nine, she worked out how to make her food synthesizer produce only spumoni ice cream by calculating the exact protein concentration and small particle dispersion of emulsifiers required. (ST: "Runaway")

Tilly described her fourteen-year-old self as a "weird" child, who didn't have a lot of friends and had no one who believed in her, including herself. (DIS: "An Obol for Charon") In 2247, Tilly attended Musk Junior High School for six months, where she befriended May Ahearn, who gave her the nickname "Stilly". (DIS: "New Eden") She transferred schools when her mother got another posting. (DIS: "Point of Light", "An Obol for Charon")

Tilly claimed to have gone through "a bit of a rebellious phase" when she was sixteen, and had hacked into something. (DIS: "Project Daedalus")

In school, her mother remembered a particularly painful time when she had more trouble climbing a wall than the other children, where Tilly chose to run away rather than confront the challenge. (ST: "Runaway")

Starfleet career[]

Tilly attended Starfleet Academy in San Francisco, and used to study under a particular tree popular among cadets. (DIS: "People of Earth")

She rated herself as the best theoretical engineer at the Academy, and was fast-tracked in order to serve aboard the Discovery, where she served in engineering. (DIS: "Context Is for Kings")

USS Discovery[]

Tilly initially had quarters of her own due to her "special needs", since she was allergic to polyester and viscoelastic polyurethane foam, which caused her to snore. (DIS: "Context Is for Kings")

According to, Sylvia Tilly was born with laryngotracheal stenosis. This condition was described as "an abnormal narrowing of the central air passageways that can cause chronic snoring and a dry throat." [1](X)

The war[]

In November 2256, she participated in her first away mission, investigating the crew's deaths aboard the USS Glenn. (DIS: "Context Is for Kings")

Although often socially awkward, Tilly came out of her shell in certain settings, such as the party held on Discovery, even showing aptitude at 20th century beer pong. During the event, Tilly rebuked romantic advances from Lieutenant Rhys. (DIS: "Magic to Make the Sanest Man Go Mad") Paradoxically, Tilly also became a social mentor of sorts to Michael Burnham and facilitated her introduction to future romantic interest, Ash Tyler. (DIS: "Lethe")


In 2257, in recognition for her role in ending the Federation-Klingon War, Tilly was awarded the Starfleet Medal of Honor. She received her officer's commission as an ensign and was placed on the command track. (DIS: "Will You Take My Hand?")

Tilly continued to serve on the Discovery, under the temporary command of Captain Christopher Pike. She participated in the Command Training Program during this time, a "terrible mistake" according to her mother. (DIS: "Brother", "Point of Light", ST: "Runaway")

Later the same year, Tilly volunteered to stay on the Discovery and accompany Burnham when she took the ship forward in time to the 32nd century, with no chance to return. She recorded a farewell message to her mother before she embarked on the journey. (DIS: "Such Sweet Sorrow")

Tilly, along with the rest of the volunteering Discovery crew, was presumed dead by Starfleet, based on the testimonies of the USS Enterprise senior staff. (DIS: "Such Sweet Sorrow, Part 2")

32nd century[]

During the 32nd century, when the Discovery first arrived, Tilly went on an away mission with Saru to find components needed to repair the ship at The Colony. (DIS: "Far From Home")

After Burnham was demoted by Saru due to insubordination, Tilly was offered the job of first officer and expressed her worried about taking the job to Stamets. At first, Stamets was not very reassuring to her and later gathered several members of the crew to express their support for her taking the position. (DIS: "Unification III")

Following the hijacking and retaking of Discovery, Tilly continued as the ship's first officer under Captain Burnham and was promoted to Lieutenant Junior Grade for her actions. Several months later in 3190, Tilly and Ensign Adira Tal were sent to assist Commander Nalas and his crew aboard Deep Space Repair Beta Six. (DIS: "That Hope Is You, Part 2", "Kobayashi Maru")

Under the guidance of Dr. Hugh Culber, Tilly began exploring outside of her "comfort zone", such as eating foods she disliked (particularly macaroni and cheese and Rigelian rutabagas), sleeping in different positions, and taking longer walks to the bridge, as well as volunteering to help Saru water the plants in his quarters. Motivated by a desire to help her find something "meaningfully unusual" to do, Saru recommended that she accompany Captain Burnham on a mission with the Qowat Milat to track down the rogue nun J'Vini. (DIS: "Choose to Live"). She later related these activities to Culber as "baby steps", wanting something more challenging.

Culber had been approached by Dr. Kovich, working as a consultant for the newly-reopened Starfleet Academy, looking for a member of Discovery's crew to lead a group of cadets in a team-building exercise. Culber recommended Tilly, with Adira Tal accompanying her at his suggestion in order to work on their own team-building skills. Despite initial resistance by the cadets and being stranded on a dangerous Class L ice moon, Tilly was successfully able to convince the cadets to work together and survive. Upon her return to Federation Headquarters, Kovich offered Tilly a teaching position at Starfleet Academy. Re-examining her career path and the events that had occurred in her life, Tilly chose to accept. (DIS: "All Is Possible")

When debris from the DMA began to hit Earth, Tilly and several cadets assisted Admiral Vance and the crew of the USS Federation in evacuating the planet. Tilly stayed with Vance aboard the Federation and reinforced Earth's shields. Fortunately, Discovery was able to convince Species 10-C to stop the DMA. Tilly later returned to Discovery to celebrate their mission's success in the crew lounge. (DIS: "Coming Home")

However, Tilly began to grow frustrated with her new job as the new batch of cadets weren't that great and being a teacher began to get boring for her. When Burnham asked her to hack into the Federation database for information on Discovery's top secret Red Directive mission, Tilly was only too happy to comply. Although she was caught by Vance, he was equally frustrated with the secrecy surrounding the mission and helped Tilly to finish the hack. (DIS: "Red Directive")

Tilly was subsequently transferred back to Discovery as a science advisor on the ship's mission to find the Progenitors' technology. Tilly confronted Commander Rayner, the new first officer following Saru's resignation to become an ambassador instead, over his behavior and offered Culber advice on his spiritual awakening while working with Stamets to try to figure out the various clues. (DIS: "Under the Twin Moons", "Jinaal", "Mirrors")

After tracking the fourth clue to Halem'no, Tilly joined Burnham on the away mission, quickly befriending the young Halem'nite Ravah who reminded Tilly a lot of one of her cadets, Ross, who was struggling with what to do with her future. While Burnham attempted to repair the High Summit -- the Denobulan weather modification tower protecting the only inhabitable part of the planet from dust storms -- Tilly ran the Journey of the Mother Compeer with Rayah, scoring a tie. However, Tilly discovered too late that the winner was sacrificed by the Halem'nites to their gods in an attempt to make it rain once again. Burnham was forced to break the Prime Directive and reveal the truth about the High Summit to the Halem'nites in order to save Tilly's life. During her time trapped in the tower, Tilly figured out the rest of the clue with Rayah's help, allowing Burnham and Tilly to collect the next map piece and clue. Tilly guessed that the lesson left on Halem'no was that technology was a massive responsibility and that they would have to be very careful when the Progenitors' technology was found. (DIS: "Whistlespeak")

When Burnham boarded Ruhn's dreadnaught to retrieve the structure containing a portal to the Progenitors' technology, Rayner offered Tilly the position of acting first officer. However, Tilly's questioning of why Rayner never took the captain's chair annoyed him and Rayner told her that he had picked her for his Number One "because you're smart as hell, you're a good leader, and if we were stuck in a foxhole together, I wouldn't kill you. That is, unless you gave me more of that warm and fuzzy encouragement that I don't need." This effectively shut Tilly up. (DIS: "Lagrange Point")

After the mission, Tilly attended Saru and T'Rina's wedding and announced that she was starting a mentorship program at Starfleet Academy. Tilly explained that her mentorship of Adira during the Red Directive mission had caused Tilly to realize that the one-on-one approach was what they were missing at the Academy. An amused Burnham then left Tilly to fend for herself after she called Rayner "crabby." (DIS: "Life, Itself")

33rd century[]

Decades later, Tilly remained close friends with Burnham and her family. She also became the longest tenured Academy instructor ever. (DIS: "Life, Itself")

Alternate timelines and realities[]

In an alternate timeline, while time cycling due to a time bug, a Captain Michael Burnham from the future visited Discovery in 2256 at a point in time when Airiam was still alive and Burnham herself was a former mutineer who was not well trusted by the crew. In order to gain the bridge crew's trust, Burnham revealed to Airiam the details of her future death. Although the rest of the bridge crew refused to believe that Airiam would die in such a way, Airiam confirmed that she would sacrifice herself in such a way if it came down to it and ordered the crew to stand down. While addressing Tilly, Burnham recalled that Tilly was afraid that Burnham would kill her in her sleep because of Tilly's snoring and reassured a nervous Tilly that that was never going to happen. Airiam, who was in charge as Gabriel Lorca was on an away mission, had Discovery taken to maximum warp and then had Detmer break the warp bubble as a part of Paul Stamets' plan. This timeline was erased when the time bug was removed before it could reset the cycle again as the changes made in each time period wouldn't become permanent until the bug reset. (DIS: "Face the Strange")

Personal relationships[]


Michael Burnham[]

Tilly and Burnham photograph

A photo of Burnham and Tilly, along with Tilly's Starfleet Medal of Honor

Upon meeting Michael Burnham, who at the time was an inmate being assigned to share quarters with Tilly temporarily, Tilly was delighted at the thought of having a roommate, stating "A roommate is like an automatic, built-in friend." While Tilly's offer of friendship was initially rebuked by a cold Burnham, and returned later in engineering, Tilly soon found herself admiring Burnham's courage. While still lacking confidence, Tilly shared her closely held dream with Burnham: that she would be a starship captain some day. Burnham, admiring Tilly's optimism, took her under her wing – often engaging in physical and dietary training together. (DIS: "Context Is for Kings", "Lethe")

Tilly kept a photograph of herself and Burnham in their quarters, next to both of their Starfleet Medal of Honor. (ST: "Runaway")

Later, she volunteered to travel to the future with Burnham in Discovery despite not being able to return home. (DIS: "Such Sweet Sorrow")

Me Hani Ika Hali Ka Po[]

Paul Stamets[]

Tilly and Paul Stamets frequently worked together on the spore drive. Tilly was one of the first to know of Stamets' side effects after injecting himself with the tardigrade DNA during the Klingon War. After Culber died, Tilly was the first to try and convince Stamets to stay on the Discovery instead of taking a job at the Vulcan Science Academy. (DIS: "Brother") When Tilly was infected by May Ahearn, he tried to help her remove the creature and tried to calm her down when she was panicking. He later went into the network to save Tilly after she had been abducted by May. (DIS: "An Obol for Charon", "Saints of Imperfection") After the jump to the future, Stamets, along with some of the other crew members, encouraged Tilly to take the job of first officer after Saru had offered it to her. (DIS: "Unification III") She was familiar enough with him to call him "Paul" instead of by rank or last name during a crisis. (DIS: "Su'Kal")

May Ahearn[]

Tilly met the real May Ahearn when she briefly attended Musk Junior High School in 2247. They frequently ate lunch together. Tilly never spoke to May again after her mother was transferred to another posting.

After being injured during an attempt to remove a piece of the dark matter asteroid, in 2257, Tilly started seeing a hallucination of Ahearn. After learning the real Ahearn had died in 2252, Tilly discovered the hallucination she was seeing was in fact a member of a species native to the mycelial network. (DIS: "New Eden", "An Obol for Charon")


Tilly respected Saru as a superior officer, and asked for his recommendation to the Command Training Program. (DIS: "The Wolf Inside") Upon acceptance, Tilly often worked with Saru as her CTP director. (DIS: "New Eden")

When Tilly tended to get overexcited and ramble informally in tense situations, Saru often advised her to maintain her professionalism. (DIS: "Light and Shadows") Though when appropriate, he also allowed her to do so if it helped her remain calm, such as when they hiked together to a settlement on "The Colony" in 3189. (DIS: "Far From Home")


Tilly indicated that she had, at various points, been interested in "musician"-types and "soldier"-types. (DIS: "Magic to Make the Sanest Man Go Mad")

Personal interests[]

Tilly had read everything there was available on Captain Philippa Georgiou, and was exceptionally excited at the prospect of meeting her after her presumed death. (DIS: "Context Is for Kings", "Will You Take My Hand?")

Tilly enjoyed espresso with milk alternative, as well as ice cream. (ST: "Runaway") She did not like cheese or macaroni and cheese. (DIS: "Choose to Live")

Memorable quotes[]

"What the heck… heck… hell? What the hell! Hold your horses!"

- Tilly, attempting to impersonate Captain "Killy" (DIS: "Despite Yourself")

"Yeah, when the people who are supposed to care about you don't listen to you, it's frightening and it's lonely, and it makes you feel like you're crazy or like you're, like, not even there. I get that."

- Tilly, reminiscing her youth to Me Hani Ika Hali Ka Po (ST: "Runaway")

"Excuse me, sir, um, respectfully, the pacing, you're making everybody nervous. You can sit in the captain's chair, you know."
"If I felt like it, I would."
"Captain Burnham, she trusts you to lead us. We all do, and it's a bit of a road to get there, but we really, um, we really do."
"You know why I asked you to serve as my Number One today, Lieutenant?"
"No, sir. Actually, I don't."
"It's because you're smart as hell, you're a good leader, and if we were stuck in a foxhole together, I wouldn't kill you. That is, unless you gave me more of that warm and fuzzy encouragement that I don't need."

- Tilly and Rayner (DIS: "Lagrange Point")




Background information[]

Sylvia Tilly was portrayed by Mary Wiseman. The character was named after the young niece of Gretchen J. Berg. (AT: "Context Is for Kings")


Tilly is the focus of the novel The Way to the Stars. Her grandmother on her mother's side is revealed to be named Adèle, while Tilly's father is named Iain and serves as a lieutenant specializing in xenoarcheology on the science vessel Dorothy Garrod since a year before Tilly's sixteenth birthday. Tilly's mention in the episode "Project Daedalus" of having run away from home at age 16 and engaging in computer-hacking was very likely a direct reference to the events of this novel, which was released prior to the TV episode.

Tilly appears in the "Age of Discovery" expansion to Star Trek Online, voiced by Mary Wiseman. In the tutorial for Discovery-era player characters, set shortly after the Battle of the Binary Stars, Tilly is a third-year cadet at the Academy, whose engineering aptitude allowed her to be chosen as chief engineer for the cadet cruise aboard a Malachowski-class vessel. When the player character, a fourth-year cadet, unexpectedly becomes the captain, Tilly remains as chief engineer until the ship returns to Earth after rescuing the miners of Corvan II, after which she parts ways with the player just before her eventual assignment to the Discovery. Tilly was also the voice for level-up notifications for Discovery-era Starfleet characters, before being replaced by Gabriel Lorca in May 2019.

External links[]