BGen Kevin Nally was commissioned a Second Lieutenant in the Marine Corps in May 1981, after graduating from Eastern Kentucky University with a Bachelor of Science in Agronomy and Natural Resources. After completing The Basic School and Communications Officer Course, he was assigned to the 1st Marine Amphibious Brigade, where he served as a Communications Platoon Commander for the Marine Service Support Group-37, and later as a Communications Platoon Commander for the Brigade Service Support Group. During this tour, BGen Nally attended SCUBA School, Pearl Harbor, where he served in an additional duty capacity as a search and rescue diver.

In 1985, he was reassigned to Marine Corps Recruiting Station, Los Angeles, California, where he served as an Officer Selection Officer. In 1988, BGen Nally attended Command, Control, Systems Course in Quantico, Virginia. After graduating in 1989, BGen Nally was assigned to the 2nd Tank Battalion, 2nd Marine Division, where he served as the Communications Platoon Commander during Desert Shield and Desert Storm. Following this, he was assigned to Communications Company, Headquarters Battalion, 2nd Marine Division as the Executive Officer.

In 1992, BGen Nally was assigned as the Operations Officer, Recruit Training Regiment, Marine Corps Recruit Depot/Eastern Recruiting Region, Parris Island. In 1995, BGen Nally was transferred to the 3rd Marine Division where he served as the S-6, then the S-3, and finally as the Executive Officer for the 4th Marine Regiment. In 1996, he served as the Commanding Officer, Communications Company, Headquarters Battalion, 3rd Marine Division. In 1998, BGen Nally was assigned as the Deputy Director, J6, United States Forces, Japan and completed a Masters in Information Systems Management.

From 2000 to 2002, BGen Nally was the Commanding Officer of Support Battalion, MCRD/ERR, Parris Island. From May of 2002 to July 2003, BGen Nally was the Director, Marine Corps Martial Arts Program. BGen Nally is a 2004 graduate of the Industrial College of the Armed Forces with a concentration in Information Strategy. Following this assignment, he served from 2004 until 2006 as the Deputy Director for C4, United States Central Command, where he deployed twice in support of OIF/OEF. In 2006, BGen Nally was transferred to Camp LeJeune, NC, where he served as the II MEF AC/S G-6 and subsequently as the II MEF Chief of Staff. From 2007 until 2009, he served as the Commanding Officer, Marine Corps Communications-Electronics School in 29 Palms, CA, and as the AC/S, G-6, MCAGCC/MAGTF-TC. He is currently serving as the Chief Information Officer for the U.S. Secret Service (November 15, 2015 – to present).

His personal decorations include the Distinguished Service Medal, Defense Superior Service Medal, Legion of Merit (with one gold star), Defense Meritorious Service Medal, Meritorious Service Medal with two gold stars, the Navy/Marine Corps Commendation Medal with three gold stars, the Navy/Marine Corps Achievement Medal, and the Combat Action Ribbon.