Stapleton played 10 seasons in the NHL, the final eight with the Black Hawks. He teamed with Bill White to form one of the League's best defense pairs in the early 1970s, helping Chicago advance to the Stanley Cup Final in 1971 and 1973. Stapleton's best offensive season was 1968-69, when he scored 56 points, including 50 assists, the most by an NHL defenseman at the time. The record didn't last long; Bobby Orr of the Boston Bruins broke it in 1969-70 with 87.
"Pat was short but he was real stocky, good on his skates," longtime teammate and Hockey Hall of Fame goalie Tony Esposito said of Stapleton, who was 5-foot-8. "He was hard to knock off the puck. They might say he was 180 pounds, but I think he was 185 or 190 when I played with him. He played with Bill White and they fed off each other. They were dynamite.
"I remember Pat could move the puck out of our zone real well, carry it and feed it off. It's important to have guys like that, guys who pick up the puck and don't give it away. He rushed when he had the chance, but he was pretty much a stay-at-home guy. Very mobile, quick and real smart. He couldn't go head-to-head with a guy who was 6-foot-3 or 6-foot-4, but he managed somehow to come out with the puck a lot."