Reilly later received his Bachelor of Business Administration in banking and finance in 1972 from Iona College in New Rochelle, New York.

He is also a volunteer for the American Cancer Society, and a past-president of the Anne Arundel County Life Underwriters Association.

[4][5] In 2022, the Maryland General Assembly's Joint Committee on Legislative Ethics found that Reilly broke with the standards of the body after he told a constituent he planned to pull a bill they both worked on because she donated to his opponent's campaign.

[9] In 2021, Reilly was one of two Republican state Senators to vote in favor of the Climate Solutions Now Act of 2021, a bill that aimed to cut Maryland's greenhouse gas emissions by 60 percent by 2030.

[18] In 2022, Reilly introduced an amendment to the state's legislative redistricting plan to again swap out the LRAC-drawn maps with those proposed by the MCRC, which was rejected by a 14-32 vote.

[20] During a debate on legislation to legalize same-sex marriage in Maryland, Reilly introduced an amendment to change the bill's effective date from October to January 2013, which did not receive a vote.

[26] The nine-mile portion of Maryland Route 450 from Crofton to Annapolis known as Defense Highway was officially renamed after Reilly on October 25, 2023.