While Mark was serving as a full-time missionary in California, the U.S. was attacked on 11 September 2001, which became one of the reasons he joined the U.S. military to fight terrorism. He received his college degree, and then enlisted in the U.S. Air Force in June 2007. He enlisted instead of becoming an officer because he knew his chances of deploying were higher as an enlisted Special Tactics airman. He wanted the toughest job the military could offer, and Air Force Combat Controller was what he was looking for.

On September 29, 2010, while conducting a combat patrol in Uruzgan Province, Afghanistan, Senior Airman Forester, a combat controller assigned to the 21st Special Tactics Squadron, and his Special Forces team encountered 30 armed insurgents and an eight hour battle ensued. At one point, while his team was pinned down with machine gun and rocket-propelled grenade fire, Forester stepped out from behind his vehicle and fired a smoke grenade to mark the enemy position and directed two AH-64 strafing runs on the target. However, the enemy force continued to fire and maneuver within 250 meters of Forester's team location, thus wounding three Special Forces operators. Recognizing the dire situation, Forester again exposed himself to enemy fire to mark the enemy location and directed a series of A-10 strafing runs. Finally, Forester ran through enemy fire to reach the front of the team's column. From there he directed two 500 pound bombs on the target from a flight of F-16s. Forester's combined actions that day resulted in 37 insurgents killed and he was posthumously awarded the Silver Star.

JAG 28, which was his call sign and the only name many pilots knew him by, was immediately retired after his death.

Most of his teammates/leaders who spoke at his funeral and memorial services ended their speeches with “Roll Tide” because they knew what a big Alabama fan he was.

View this Silver Star citation here: CLICK HERE