Wilson Reilly was born in Waynesboro, Pennsylvania. He attended the common schools, and was engaged as a hatter in Waynesboro and Chambersburg, Pennsylvania. He studied law, was admitted to the bar in 1837 and commenced practice in Chambersburg. He served as prosecuting attorney of Franklin County, Pennsylvania, from 1842 to 1845. He was an unsuccessful Democratic candidate for election in 1854.

Reilly was elected as a Democrat to the Thirty-fifth Congress. He served as chairman of the United States House Committee on Expenditures in the Department of War during the Thirty-fifth Congress. He was unsuccessful candidate for reelection in 1858. He became captain of the McClure Rifles [FALSE!] and joined the Pennsylvania Reserve Corps [FALSE!] at Camp Curtin in Harrisburg, Pennsylvania. He resumed the practice of law. In 1885, he and died in Chambersburg and was buried in Falling Spring Cemetery.

NOTE: Where the above author got the idea that Congressman Wilson Reilly served in the army during the Civil War is a mystery as there is no such evidence. The congressman's son Wilson served but not with any regiment in the Pennsylvania Reserve Corps. The McClure Rifles Militia from Franklin County, Pennsylvania, served as the recruiting base for Co. K, 12th Pennsylvania Reserves (41st Pennsylvania Infantry), but there is no one named Reilly or any similar spelling in the muster roll either in Co. K or the staff register.

• United States Congress. "Wilson Reilly (id: R000157)". Biographical Directory of the United States Congress. Retrieved on 2008-02-14
• The Political Graveyard