Christopher Dale Flannery was born on February 12, 1949, in Brunswick, Victoria, Australia. Raised in a working-class neighborhood, he experienced a turbulent childhood, including alleged abuse and abandonment by his father. Flannery left school at 14 and quickly became involved in criminal activities, receiving his first conviction the same year.

By 17, he had been convicted of housebreaking, car theft, assaulting police, carrying firearms, and rape, leading to a seven-year prison sentence. During his incarceration, he befriended fellow inmate Ray Mooney, who would later become a playwright and author.

After his release from prison, Flannery initially worked as a bouncer but soon transitioned into contract killing, earning the moniker "Mr Rent-a-Kill." He was implicated in several high-profile murders, including that of barrister Roger Anthony Wilson in 1980 and Sydney brothel owner Raymond Francis "Lizard" Locksley in 1979. However, he was acquitted in both cases.

Flannery became deeply involved in Sydney's gangland wars during the early 1980s, aligning himself with notorious figures like George Freeman and Neddy Smith. His alleged involvement in the attempted murder of undercover detective Michael Drury in 1984 further escalated tensions.

On May 9, 1985, Flannery disappeared after reportedly receiving a phone call from Freeman requesting a meeting. Unable to start his car, he called Freeman, who advised him to take a taxi. Flannery was last seen leaving his apartment building; he never arrived at the meeting and was never seen again.

In 1997, the New South Wales State Coroner concluded that Flannery was murdered around the time of his disappearance, with suspicions pointing toward corrupt police officers and underworld figures.