Kimbrell received her commission in 1998 after graduating from the USAF Academy, later she attended Undergraduate Pilot Training at Laughlin AFB, TX and was awarded her pilot wings in August 1999. She then completed Introduction to Fighter Fundamental training at Randolph AFB, TX in November 1999. In August 2000, she graduated from her initial F-16 training at Luke AFB, Arizona, becoming the first African American female fighter pilot in the USAF.

She was assigned to the 13th Fighter Squadron, Misawa, Japan for her first operational assignment. During this time she was deployed to Turkey and Saudi Arabia in support of Operation Northern and Southern Watch. Her flights in Operation Northern Watch marked her as the first female pilot to fly combat missions for Misawa's 35th Fighter Wing. Additionally, during Operation Northern Watch she became the first African American female pilot to employ ordnance in combat.

In July 2004, she graduated from the Joint Fire Control Course and was assigned to the 15th Air Support Operations Squadron. Later she deployed as the 2nd Brigade Air Liaison Officer in support of Operation Iraqi Freedom.

In June 2007, Kimbrell was assigned to the 31st Fighter Wing, Aviano AB Italy where she served as Assistant Director of Operations for the 555 Fighter Squadron.

In 2009, Kimbrell relocated to 6th Combat Training Squadron, Nellis AFB where she served as the Course Manager for the Air Liaison Officer Qualification Course and an instructor. From this assignment she separated from active duty Air Force and transitioned to the Air Force Reserves in Oct 2013.

Beginning October 2013, Kimbrell served as an MQ-9 Pilot and Mission Commander for the 78th Attack Squadron out of Creech Air Force Base, Nevada.