This page contains information regarding Star Trek: Lower Decks, and thus may contain spoilers.
One of the many things that Ensign Mariner griped about was how Lieutenant Commander Andy Billups had once called her "Jen" because he'd never bothered to learn her name prior to finding out she was Captain Freeman's daughter. After Boimler was promoted to lieutenant junior grade and transferred to the USS Titan, Jen was one of the people who yelled at Mariner to be quiet and stop yelling into her PADD. (LD: "No Small Parts")
She interrupted a holo program that Mariner was running, criticizing Mariner's choice of exercise. In reply to Mariner's followup question, Shr'eyan stated that she exercised by doing yoga. She then informed Mariner that the Captain was awaiting Mariner in her Ready Room. (LD: "Strange Energies")
Sh'reyan was a prominent member of the Redshirts club on the Cerritos. When Boimler was invited to join the Redshirts, Sh'reyan helped give him a makeover by modifying his uniform, and restyling his hair. When Ensign D'Vana Tendi was transformed into a scorpion-like creature, and went on a rampage through the mess hall, she tried to inspire the crew with a rousing speech, but her speech was overlapped by other speeches of the members Casey and Castro. Boimler made an impression on Sh'reyan when he took action to help Tendi revert back to her normal self. Later on, when Casey kicked Boimler from the Redshirts, Boimler criticized the club, saying that it was shameful to try and build a persona from other captains. His actions and words were enough to convince Sh'reyan to leave the club, along with Castro, and a Kzinti ensign. (LD: "The Spy Humongous")
Sh'reyan attended the intro for the simulation drills. She was seen discussing with Winger Bingston, Jr. about the drill instructor's species. She then stood alongside Winger and Castro as they listened to the instructor's speech, with Sh'reyan and the rest of the lower decks crew showing excitement at the instructor's proposal. A holographic version of her appeared in The Naked Time simulation where she was seen naked and kissing a holographic Barnes. (LD: "I, Excretus")
Sh'reyan was later seen creating pottery with other members of the crew. She became frightened when Shaxs started to turn violent after being reminded about Bajor. Later she was seen sitting at a table and having a discussion with Castro. (LD: "wej Duj")
Sh'reyan bumped into Mariner who was carrying contraband. In response to Mariner's accusation about Sh'reyan being proud of catching her with contraband and asking that she not mention it to Ransom, Sh'reyan casually remarked that she didn't care. When Mariner claimed that she probably hated Mariner, Sh'reyan replied that she didn't even think of Mariner at all.
Later, Sh'reyan was on the bridge, suited up in a spacesuit like the rest of the crew and informing the captain that they were approaching the debris field as planned. She then warned the bridge crew about the incoming debris that was about to hit the ship. As the ship made impact, Mariner was knocked from the bridge and floated out into space. Sh'reyan then walked onto the outside surface of the ship and prevented Mariner from drifting away from the ship. The two then made it back to the bridge.
Sometime later, Sh'reyan was enjoying a drink when Mariner approached her, thanking Sh'reyan for saving her life. Sh'reyan then dismissed the compliment and apologized for treating Mariner badly the past year. The two then admitted their real feelings for each other before they approached Boimler to congratulate him for saving the ship. Sh'reyan then joined in toasting the captain and followed her outside her Ready Room in preparation for celebrating her promotion to Admiral. She, like the other crewmembers initially cheered the captain as she came out of the room but was quickly moved to shock when she noticed that the captain had actually been arrested. (LD: "First First Contact")
Sh'reyan was voiced by Lauren Lapkus.
She was portrayed as a non-speaking background character until "No Small Parts" in which she was heard off screen. Her first on screen speaking appearance was in "Strange Energies". Jennifer's name was first mentioned in "Cupid's Errant Arrow", her Human-sounding first name is a result of Tawny Newsome improvising.  Sh'reyan's second name was shown on screen in "I, Excretus".
According to the Andorian naming conventions introduced in the Pocket Books novels, the "sh" prefix in Sh'reyan's last name indicates that she is a "shen", one of the four Andorian genders.