Len Patrick entered the U.S. Air Force Academy in June 1977, and was commissioned a 2d Lt in the U.S. Air Force on May 27, 1981. His first assignment was as Chief of Readiness and Logistics, Chief of Resources and Requirements, and as an Air Force Military Construction programmer with the 15th Civil Engineer Squadron at Hickam AFB, Hawaii, from July 1981 to July 1984, followed by service in an Education with Industry Position with the Illinois State Water Survey at the University of Illinois Campus from August 1984 to June 1985. Capt Patrick served as a Military Construction manager, as a 3rd Air Force facility programmer, and as Chief of the Program Control Branch for the 401st Tactical Fighter Wing Relocation Program with Headquarters U.S. Air Forces in Europe at Ramstein AB, West Germany, from July 1985 to June 1989, and then as Construction Manager and Integrated Program Manager with the Logistics Support Group at Riyadh, Saudi Arabia, from July 1989 to July 1991. His next assignment was as an Action Officer with the Civil Engineer Programs, Directorate of Plans and Programs, Office of the Civil Engineer with Headquarters U.S. Air Force in the Pentagon from August 1991 to July 1993, followed by Air Command and Staff College at Maxwell AFB, Alabama, from August 1993 to June 1994. LtCol Patrick served as Commander of the Operations Flight, 21st Civil Engineer Squadron at Peterson AFB, Colorado, from July 1994 to August 1996, and then as Chief of the Facility Requirements Branch with Headquarters Air Combat Command at Langley AFB, Virginia, from August 1996 to July 1999. His next assignment was as Commander of the 12th Civil Engineer Squadron at Randolph AFB, Texas, from July 1999 to July 2001, followed by Air War College at Maxwell AFB from August 2001 to June 2002. Col Patrick served as Commander of the 60th Support Group and then the 60th Mission Support Group at Travis AFB, California, from July 2002 to August 2004, and then as Deputy Director of Operations for Technical Training with Headquarters Air Education and Training Command at Randolph AFB from August 2004 to April 2005. His next assignment was as the Civil Engineer with Headquarters Air Education and Training Command at Randolph AFB from April 2005 to July 2006, followed by service as Director of Installations and Mission Support with Headquarters Air Mobility Command at Scott AFB, Illinois, from July 2006 to January 2008. Brig Gen Patrick served as Commander of the 37th Training Wing at Lackland AFB, Texas, from January 2008 to July 2009, and then as Commander of the 502nd Air Base Wing at Fort Sam Houston, Texas, from July 2009 to July 2011. His next assignment was as Commander of 2nd Air Force at Keesler AFB, Mississippi, since from July 2011 to July 2014, and then as Vice Commander of Air Education and Training Command at Joint Base San Antonio-Randolph, Texas, from July 2014 until his retirement from the Air Force on September 1, 2016. Gen Patrick received a Bachelor of Science degree in civil engineering from the U.S. Air Force Academy in 1981, a Master of Science degree in mechanical engineering from Boston University in 1988, and a Master of Strategic Studies degree from the Air War College in 2002.

His 4th Legion of Merit Citation reads:

Brigadier General Leonard A. Patrick distinguished himself by exceptionally meritorious conduct in the performance of outstanding services to the United States as Commander, 37th Training Wing, Air Education and Training Command, Lackland Air Force Base, Texas, from 25 January 2008 to 24 July 2009. During this period, General Patrick commanded the most populous base in the Air Force with 45,000 military, civilian, and contractor personnel and 70 associate organizations. His extraordinary leadership was instrumental in replenishing the combat capability of the Air Force and building strong coalition partnerships. Under his command, the 37th Training Wing graduated 48,764 mission-ready Airmen from Basic Military Training, 42,922 Airmen in 30 Air Force specialties from technical training, and 4,767 international students representing 110 countries from the Defense Language Institute English Language Center and the Inter-American Air Forces Academy. Under General Patrick's direction, the largest transformation of Basic Military Training in 50 years occurred with the expansion from six and one-half to eight and one-half weeks of training. The centerpiece of this historical expansion was inclusion of the 25 million dollar Basic Expeditionary Skills Training; a realistic five day, deploy, employ and redeploy scenario where trainees execute combat skills learned in the previous six weeks resulting in the inculcation of the warrior ethos needed in today's expeditionary Airmen. General Patrick's leadership was evident as his team spearheaded the reception effort of 390 special needs and ambulatory patients, 700 evacuees, and postured the base for 1,289 United States Northern Command joint forces for Hurricanes Gustav and Ike relief efforts. These tremendous efforts were recognized when the President of the United States visited Lackland Air Force Base to express his personal thanks for a job well done. General Patrick's tireless efforts ensured Lackland's status as one of the Air Force' showcase wings by garnering Air Education and Training Command's 2008 installation Excellence Award. Further, General Patrick's tenure at Lackland Air Force Base culminated in his and Mrs. Patrick's recognition as the Air Education and Training Command General and Mrs. Jerome O'Malley award recipients as the wing commander and spouse team who best exemplify the highest ideals and positive leadership of a military couple serving in a key Air Force position. The superior initiative, outstanding leadership and personal endeavor displayed by General Patrick reflect great credit upon himself and the United States Air Force.