That year, Bailey was on duty during a star mapping mission that same year, when, on the third day, the Enterprise encountered a warning buoy, and later the First Federation flagship Fesarius. The tension of the encounter detracted from the gung-ho lieutenant's performance and might have ruined his career.
Initially relieved of duty for a near nervous breakdown, he requested permission to return to his work even though the ship was apparently seconds from being destroyed, confirming Kirk positively assessing his character and fitness for bridge duty.
At the conclusion of the encounter, when Kirk put together an away mission to visit Balok's pilot vessel, he offered to take Bailey, to give him "a look at the unknown." When Balok commented how lonely he was, and suggested that even an alien would be welcome company, Kirk looked to Bailey. Balok assumed he represented the Federation's best, but Bailey confessed he did not considering he made many mistakes. However, Kirk suggested that would mean Balok would have a more honest look at the Federation citizenry, which Balok welcomes. On that understanding, Bailey eagerly volunteered. (TOS: "The Corbomite Maneuver")
Bailey's given name, Dave, was not spoken on screen, but rather, appeared in the closing credits and the script of "The Corbomite Maneuver". Star Trek: The Magazine Volume 1, Issue 13, p. 88, lists him as David Bailey.
In the final draft of the teleplay (dated 3 May 1966), Bailey was the communications officer, with the navigator being an ultimately unrealized character called "Ken Easton". When Nichelle Nichols was cast as Communications Officer Uhura, however, Bailey became the navigator. Bailey didn't venture aboard Balok's pilot vessel in the final draft; instead, his last line in the script was to state, "We should never have come back."
Kellam de Forest referred to Bailey as the Enterprise's communications officer in a series of research notes he issued about an early version of "What Are Little Girls Made Of?" (on 11 May 1966). De Forest included the reminder about Bailey in a note concerning the fact that Alden had been referred to as the Enterprise's communications officer in that episode's early development.
Bailey was also included in a revised draft of the script for "Mudd's Women", written by John D.F. Black and issued on 17 May 1966. In a scene from that script, Bailey made a notation on "a pad" while seated at his station on the bridge. In a letter written by Robert Justman and sent to Black the day after the script was submitted, Justman half-jokingly said about Bailey, "I don't think he would have a pad. Although, he might have a pad back on Earth where he takes chicks to have a good time." Ultimately, Bailey was excluded from "Mudd's Women" at the behest of Gene Roddenberry, who – in a memo to Black (dated 19 May 1966) – proposed, "Since we have no way of knowing which show will air first, it is probably best we play safe with another Navigator under another name."
In the revised final draft of the script for "The Corbomite Maneuver" (dated 20 May 1966), Bailey was described as "a strong-faced young man who will be sharp and competent at first impression. But we will begin to see bit by bit beneath his surface traces of uncertainty and immaturity – a young officer with a job and responsibility he is not yet seasoned enough to handle." The same version of the teleplay did include Bailey's visit to Balok's pilot vessel but, in an ultimately unused line of dialogue, he admitted feeling afraid before going aboard the craft.
Bailey was also featured as a communications officer in "The Galileo Seven", during early development of that episode, such as in a revised draft of the installment's teleplay. In a memo Robert Justman sent John D.F. Black in regard to that script draft (the memo was dated 25 May 1966), Justman advised, "It might be better to give a different name to the Communications Officer."
The My Brother's Keeper novel Constitution establishes that Bailey was born on Earth in 2241 and graduated from Starfleet Academy in 2263, where he was then assigned to the USS Carolina. While aboard the Carolina, he served with distinction, earning himself a couple of medals and a promotion to lieutenant junior grade in the process, as well as high recommendations by her commanding officer. By 2265, Bailey was now serving aboard the USS Potemkin as navigator. Following the death of the USS Enterprise's navigator, Gary Mitchell, Captain Kirk successfully requested that Bailey be reassigned to the Enterprise to serve as alpha shift navigator. He was teamed with the ship's new helmsman, Hikaru Sulu.
In the third issue of the IDW Publishing comic Star Trek: Spock: Reflections, Bailey was the navigator on duty when the Enterprise came to the assistance of the stricken USS Collins. Kirk ordered Bailey and Sulu to coordinate in using the ship's tractor beams and transporters to get all of the Collins' escape pods safely aboard before the Soyuz-class ship suffered a warp core breach.
Bailey figures heavily in the 2017 novel The Face of the Unknown, written by Christopher L. Bennett. He has matured from his earlier fearful state and has been the unofficial ambassador to the First Federation since leaving the Enterprise.
In the Star Trek: Voyager short story "Ambassador at Large" from the anthology book Strange New Worlds, Bailey explored the Alpha Quadrant with Balok for around twenty years. After that, the two decided to continue their explorations into the Delta Quadrant. Their next contact with anyone from the Federation came in 2373 when Captain Kathryn Janeway and the crew of the USS Voyager rescued Bailey from the Mondasians. Though extremely pleased to see other Humans again (and to sample replicator cuisine), Bailey rejoined the Fesarius to continue his travels.