Medavoy grew up in suburban Long Island and originally planned to be an English teacher, but due to a school hiring freeze instead followed the example of relatives and joined the NYPD in 1976.

[1] Despite his faults, he was actually a skilled detective who earned respect through his tenacity and inventiveness; he had a knack for talking people into doing things they were initially reluctant to do, including coming to the police station to be questioned, or confessing to a crime.

This skill earned him a commendation when Medavoy went into a 15th Precinct holding cell undercover and tricked a conman into confessing by pretending to be interested in learning how to execute the con himself.

[5] He was also sidetracked occasionally by thoughts of money making opportunities based on people he met in his police work, including dog breeders, and a conman who sold a book claiming it was possible to legally avoid paying federal income taxes.

Medavoy also overcame a witch hunt by Lt. Bale, who turned him in to Internal Affairs and tried to wreck his career after learning he was employed part-time at a bar, though it was against regulations for off-duty police officers to work at establishments that serve alcohol.

[13] In the final few episodes, Medavoy retired in order to join the real estate business; the interpersonal skills he had developed as a detective enabled him to close a sale for his new girlfriend Bridgid, whom he had met on a fraud case, and she invited him to come to work with her.

[14] At his retirement party, Greg expressed his love for his career and coworkers, and closed with the traditional NYPD toast "to the guy that invented this job".