Stanley was signed as an undrafted free agent by the Philadelphia Flyers in 1981. After closing out his junior career with the Saskatoon Blades, he turned pro in 1982. After two solid seasons in the minors, he made his NHL debut in 1983–84, appearing in 23 games down the stretch for the Flyers (and scoring his first NHL goal) along with all three of the team's playoff games. However, his career would undergo a setback the following season, as he suffered career-threatening injuries in a car accident while playing for the Hershey Bears, Philadelphia's American Hockey League affiliate, and missed most of the year.
However, Stanley would battle back, and established himself as a full-time member of the Flyers after being called up again midway through the 1985–86 season. Blessed with limited natural talent, Stanley was able to stick in the NHL as a useful utility player primarily due to his size and grit, along with his versatility. While his natural position was on the blueline, he would see much of his NHL action as a forward where his size and toughness allowed him to serve as an enforcer. He appeared in 33 games for the Flyers in 1986–87, and dressed in 13 playoff games as Philadelphia reached the Stanley Cup Finals before losing to the Edmonton Oilers.
For the 1987–88 season, Stanley was dealt to the Vancouver Canucks. In Vancouver, he received a chance to play more regularly, and responded with his best NHL season, recording 2 goals and 9 points in 57 games along with 151 penalty minutes. He would set a career high with 3 goals in 1988–89, although injuries limited him to just 20 games. After seeing action in just 23 games in the 1989–90 campaign, he retired.
Stanley finished his NHL career with 8 goals and 17 assists for 25 points in 189 games, along with 408 penalty minutes.
Following his retirement, Stanley would become a hunting guide, specializing in ducks and waterfowl, and he currently operates a hunting lodge outside of Winnipeg, Manitoba. His middle son Matthew plays for the Lethbridge Hurricanes of the Western Hockey League (WHL).