- "I never trusted you, from the moment I saw you."
- — Steve Coyne
Steve is an enforcer for the Vinci family. He grew up in rural Birkland, moving to the city at the age of sixteen. While being arrested for battery, Steve badly beat an EBPD officer and was sentenced to ten years, of which he served five. It was in prison that he started working as muscle for fellow inmate Derek Pappalardo, a relationship that continues on the outside. Steve can never be a full member due to his Dutch-Irish heritage, but became the family's most trusted associate after he assisted in the assassination of rival boss Tomaso Moretti to end the Vinci-Moretti War. 
Steve serves as Derek's right hand and most trusted associate. As such he is responsible for doing Derek's dirty work, like killing Vito Scaletta's father Antonio by drowning him in 1943. In April of 1951, he assists Vito Scaletta and Joe Barbaro in their assault on the greasers after they destroyed a truck load of cigarettes they were selling in Greaser territory. Steve gets involved because he wants payback for them trashing his cousin's car, robbing him, and knocking out three of his teeth.
Several months later, Vito Scaletta was assisting Derek and Steve with a labor dispute at the docks. Over the course of the negotiations, Vito's name is mentioned and an Old Dockworker recognizes him as Antonio Scaletta's son, who asks why Vito is working for Derek after what he did to his old man. Steve immediately tells the man to shut his mouth but another worker speaks up, telling how Derek and Steve killed Vito's father. When pressed for answers, Steve finally admits to drowning him. After finding out the truth about his father's death, Vito goes after Derek and Steve, killing them and anyone else who gets in his way.
- A younger fully haired Steve can be seen in The Old Country. He is the man that picks Antonio Scaletta for a job.
- He can be seen reading Playboy magazines in multiple cutscenes.
- There was a cut side mission where Steve gave Vito a job destroying some cars. This was later reworked as Going out of Business and added to Joe's Adventures.