Corporal J. McKenzie
Corporal J. McKenzie was a MACO assigned to the starship Enterprise NX-01.
Prior to her stationing aboard Enterprise, McKenzie did a six week tour on Jupiter Station, where she learned to use gravity boots, after the gravity plating had gone down a few times on the station. (ENT: "Anomaly")
On the alternate Enterprise sent back into 2037 while traveling through an unstable subspace corridor, McKenzie and Travis Mayweather became a couple and later married. When asked by Hoshi Sato if Travis knew her, he stated, "We talked after a training session once," to which Sato suggested that perhaps he should "ask her out." (ENT: "E²")
Major Hayes nominated McKenzie as his successor when he was mortally wounded in action aboard a Xindi-Reptilian warship, stating that "she knows the team," and to "rely on her." (ENT: "Countdown")
Background
J. McKenzie was played by actress Julia Rose; her only appearance was in "Anomaly". Her EV undersuit was sold off on the It's A Wrap! sale and auction on eBay. [1]
In the non-canon novel Last Full Measure her first name is listed as Fiona, although her on-screen uniform ID patch carries the initial "J".