Clarke had three 100-point seasons, twice leading the league in assists, and was selected to play in nine NHL All-Star Games. He also won the Frank J. Selke Trophy in 1983, as the league's best defensive forward.

Upon retiring at the end of the 1983–84 season with 358 goals and 852 assists for a total of 1,210 points in 1,144 career games, he immediately became general manager of the Flyers. He spent 19 of the following 23 seasons as a general manager of the Flyers, also briefly serving as general manager of the Minnesota North Stars and Florida Panthers, and reached the Stanley Cup Finals three times with the Flyers and once with Minnesota. His time as an NHL general manager had its share of controversy, perhaps none greater than the rift between him and star player Eric Lindros during the late 1990s and early 2000s. He resigned from the general manager position less than a month into the 2006–07 season and is currently the Flyers' senior vice president.

The image of Clarke, with a toothless grin, embracing the Stanley Cup and winking following the Flyers' victory in the 1975 Stanley Cup Finals is considered one of the most iconic and famous photos in the history of the sport of hockey.

Records

Clarke finished his career 4th all-time in assists and 11th all-time in points, but he has since fallen to 25th all-time in assists and 46th all-time in points (as of completion of the 2020–21 NHL season). His career plus-minus of +507 is 5th all-time. His back-to-back 89 assist seasons in 1974–75 and 1975–76 is still the Flyers team record and he also owns several other Philadelphia Flyers records, including: