Gavin was a Human botanist who worked on Earth in the late 24th century.
In 2381, Gavin visited historical Bozeman, where he boarded Phoenix replica number five at the Ride the Phoenix attraction. He was nervous, as he did not deal well with spaceflight, and was unaware that the other four passengers – Beckett Mariner, Brad Boimler, D'Vana Tendi, and Sam Rutherford – were planning to commandeer the craft to reach the USS Cerritos in drydock.
After arriving at the Cerritos, Rutherford offered to restore the Phoenix's automation to return Gavin to Earth. However, Gavin had been seized by the thrill of adventure during the unauthorized jaunt and declared that he was no longer a botanist but a pilot, and that he would take the ship to explore the galaxy. A short time later, Starfleet recovered the Phoenix near the moons of Jupiter; the self-declared "Captain" Gavin, ranting that he was "on a trek amongst the stars", had to be physically dragged off the theme park ride. (LD: "Grounded")