Xavier MacMillan

Xavier was the Chief of Starfleet Research and Development at Starfleet Headquarters in the late 23rd century. (Star Trek: The Intrepid Adventures)

Early life before Starfleet
Xavier was born on May 17, 2225 human calendar time at Wichita, Kansas on Earth.

Trivia
Fleet captain MacMillan dined off of Lieutenant Raymond Gatling's Gatling Phaser Gun project. - (Gatling's Gun)

Chronology

 * 2225: Xavier is born on Earth in Wichita, Kansas.
 * 2243: Xavier enters Starfleet Academy
 * 2247: Xavier graduates Starfleet Academy, and is promoted to Ensign. The first assignment is the USS Constitution as an engineer.
 * 2250: Xavier is promoted to Lieutenant junior grade and assigned to the USS Enterprise as an engineer.
 * 2253: Xavier is promoted to full Lieutenant and assigned to the USS Bridger as the Chief Engineer.
 * 2256: Xavier is promoted to Lieutenant Commander and is made the Chief Engineer on the USS Excalibur.
 * 2259: Xavier is promoted to full Commander and assigned to the USS Merrimac as the First Officer.
 * 2264: Xavier is promoted to Captain and is the Captain of Engineering at Starbase 3.
 * 2270: Xavier is promoted to Fleet Captain and is made Chief of Starfleet R & D at Starfleet Headquaters.