Glennon is a former corrupt police detective of the Freeland Police Department.
Glennon joined the Freeland Police Department, eventually rising to the rank of police detective. He was eventually coerced with money by the A.S.A. to help them with their illegal actions, using the money to buy his son a new house.
In 2018, Glennon and Deputy Chief Cayman met with Kara Fowdy, agreeing to plant some Green Light on Jefferson Pierce. The following morning, a number of police went to search Pierce's car, Glennon planting the evidence and subsequently "finding" it. They went to his office, "finding" more, before arresting him. Shortly after, Glennon was called into Inspector Henderson's office, where Henderson explained that he knew about his illegal acts, having him dead to rights, and so Glennon confessed, also giving up Cayman. He was subsequently arrested.