Sean Quinlan was born on July 31, 1963. He was raised in Scottville, Michigan and graduated from Mason County Central High School in 1981. He attended Grand Valley State University in Grand Rapids, Michigan before enlisting in the Marine Corps in December 1985 and shipping to recruit training at Marine Corps Recruit Depot San Diego.

Upon completion of recruit training and the Infantry Training School, Private First Class Quinlan was assigned to Bravo Company, 3rd Light Armored Vehicle Battalion, 1st Marine Division where he was promoted to Lance Corporal and subsequently promoted meritoriously to Corporal. Upon completion of duty at 3rd Light Armored Vehicle Battalion, Corporal Quinlan received orders to Marine Security Forces, Marine Barracks, Hawaii. Prior his arrival, he was promoted to Sergeant. Sergeant Quinlan served in Hawaii from 1990-1993 until being transferred to 2nd Light Armored Infantry Battalion, where he served as a platoon commander, platoon sergeant and vehicle commander and deployed to the Caribbean in support of Operation Support Democracy in 1994. During this tour of duty, Sergeant Quinlan was accepted into the Meritorious Commissioning Program and reported to Officer Candidate School, Quantico, Virginia in 1996. ​

Upon completion of the Officer Candidate Course, Sergeant Quinlan was commissioned a Second Lieutenant.  He completed The Basic School, where he was an honor graduate and received a meritorious augmentation, and attended the Infantry Officer Course. Upon graduation, Lieutenant Quinlan reported to Bravo Company, 3d Light Armored Reconnaissance Battalion, 1st Marine Division and deployed as a platoon commander in support of Operation Native Fury in Kuwait. Upon completion of this deployment, Lieutenant Quinlan returned to assume the duties of executive officer for the following two and a half years. During that time, he deployed to Okinawa for an eight month deployment and participated in Operation Crocodile 2000 in Brisbane, Australia.  

​In June of 2000, Lieutenant Quinlan reported to Central Michigan University for the Degree Completion Program where he was promoted to the rank of Captain.   After graduating with honors and a Bachelors of Science degree in Social Science, he reported to Headquarters, Marine Corps in Quantico, Virginia and served as the Assistant Unit Head of MMEA-82, Enlisted Assignments for Combat Arms Section.  Upon completion of his manpower tour, Captain Quinlan received orders to 2nd Light Armored Reconnaissance Battalion. He briefly served as the assistant operations officer before assuming command of Delta Company in December of 2004.  In 2005, Delta Company deployed in support of Operation Iraqi Freedom. Captain Quinlan was promoted to Major in October 2006. Major Quinlan and Delta Company returned to Iraq in 2006 and operated in the in Western Al Anbar Province.  

Major Quinlan earned his Graduate Degree in 2008 and was selected for Recruiting Station Commanding Officer where he was placed in charge of the officer and enlisted recruiting for Recruiting Station Des Moines, Iowa.  Known as the Wolfpack Nation, Major Quinlan’s command operated 25 offices that spanned five states and 160,000 square miles.  During his tenure, Recruiting Station Des Moines earned the Commandant’s Superior Achiever Award for Excellence in Recruiting three consecutive years, which was a first for the command.     ​

Major Quinlan’s personal decorations include the Bronze Star (with Combat Distinguishing Device “V”), Meritorious Service Medal, Navy and Marine Corps Commendation Medal (second award), Navy and Marine Corps Achievement Medal (third award), Good Conduct Medal (third award) and the Combat Action Ribbon.

​Major Quinlan was selected for promotion to Lieutenant Colonel in 2012 and was scheduled to be promoted that year. However, he decided to retire to spend more time with his family. Major Quinlan served in the Marine Corps for 26 years and nine months. ​​

Upon retirement in 2012, Sean taught and coached football at Des Moines North High School. He currently substitute teaches & coaches football at Clarke High School in Osceola, Iowa. He and his wife of 37 years reside in Waukee, Iowa. They are proud parents of two daughters and a son and have been blessed with three grandchildren.