Military career

Keegan joined the United States Marine Corps at a young age and was proficient in rifle training. He later made it into the Force Reconnaissance, attained the rank of Sergeant, and became a Scout Sniper. Sometime later after serving and gaining combat experience on the battlefield, he joined the Ghosts. He was one of the original fifteen, at the time of Operation Sand Viper in 2005.

Keegan continued to serve alongside Elias and Merrick. He would later first be seen on a recon patrol in No Man's Land with Merrick and Ajax. After linking up with recon team callsign Viking, Hesh and Logan's team at the time, they move in to extract Ajax at the stadium. First they recon the stadium, then they assault the facility. During the battle of Fort Santa Monica he is seen near the end of the mission extracting Hesh and Logan.

He participates in a mission to secure a High-Value-Target with intel on Rorke's location. After completing the objective Rorke blows the building and Keegan must extract with Logan and Hesh from the 52nd floor by parachuting out the window which they succeed in doing.

A little later he takes part in the assault on the facility where Rorke is suspected of being. After securing Rorke on their plane they are ambushed and stuck behind enemy lines. Logan regroups with his father Elias and Keegan who proceed with linking up with Hesh and Captain Merrick. After the team regroups they proceed with escaping and evading hostile forces in the area, until being extracted in the river by a forward recon team.