After graduating from the Advanced Course, he was assigned to the 5th Infantry Division, at Fort Polk, Louisiana, from 1992 to 1993, as a Class IX Accountable Officer.

After completion of Company Command, he served as the Task Force XXI Combat Systems Manager, 4th Infantry Division.

From 1996 to 1999, Kirklin was assigned to Hohenfels, Germany, where he functioned as the Combat Service Support Observer/Controller on the Grizzlies and Timberwolves Maneuver Teams, and later as the Operations Group S4.

In 2004, Kirklin returned to Fort Hood, and was again assigned to the 1st Cavalry Division DISCOM, as Deputy Commander while deployed to Taji, Iraq, during Operation Iraqi Freedom.

As commander, he deployed the battalion to Operation Iraqi Freedom 2006–08, Diyala Province, Iraq, and then recovered the unit back to Fort Hood.