Young Riley stuck with the game in spite of the absence of many black role models in the sport. As such, he held no aspirations of pursuing hockey as a big-league career. His course, however, underwent a dramatic change in 1973 while working in a factory and playing senior hockey with the Kimat Seniors in British Columbia. Future NHL coach Tom McVie was in the process of fortifying his lineup for the Dayton Gems of the IHL. He discovered Riley in Kitmat and invited him for a tryout. Riley accepted and made the club in 1974.

In the IHL, Riley established a reputation as a combative winger who could fight and effectively muck in the corners to set up his line mates. In 1976, McVie was appointed head coach of the Washington Capitals. With intimate knowledge of Riley's abilities, he brought him along to add intelligent toughness to his lineup. The plan worked for two seasons as he scored points and fought battles.

But when the Winnipeg Jets entered the NHL in 1979, they claimed Riley in the Expansion Draft. He failed to catch on with the club, however, and was sent down to the minors after only 14 games. Riley's frustrating experience with the Jets convinced him that coaching would be a stronger long-term career option. His dilemma, however, was rooted in the experiences of the first black professional players, Herb Carnegie and Willie O'Ree. Would there be any openings in the world of hockey for a black coach?

Riley bided his time in the AHL with Nova Scotia, New Brunswick, and Moncton. While winding his playing career down he began to study to coaching side of the game, assisting with practices and instructing younger players. Riley's wait required a lot of patience, but finally, in 1989-90, he landed a head coaching position with the Amherst Ramblers of the Nova Scotia Junior Hockey League.