Bob Errey designed his game around quickness and speed, knowing that his small stature was not going to scare off to many opponents. In junior, Errey was known as one of the fastest players in the OHL while playing three seasons with the Peterborough Petes. In his draft year, Errey lit up the scoreboard, putting 53 pucks in the net while assisting on 47 others for a 100-point season. It was that great offensive output that led to Errey's going in the first round, 15th overall, to the Pittsburgh Penguins in the 1983 Draft.
Errey made the team in 1983-84 as a 19-year-old. The Penguins were among the league's worst at the time and were in the midst of rebuilding. They were still a year away from acquiring Mario Lemieux from the QMJHL's Laval Voisins.
In that first year, Errey played in 65 games, scoring nine goals and 13 assists. But, being at least a partial victim of poor players with him, Errey's production was lower than the team desired, so they felt a year in the minors would help his development. He played 59 games with the Baltimore Skipjacks, seeing just 16 games of action with the Pens.
It was not until the 1986-87 season that Errey was inserted into the lineup on a full-time basis, dressing for 72 games with Pittsburgh and scoring 16 goals and 34 points. His best individual season was in 1988-89 when he scored 26 goals and 32 assists for 56 points in 76 games. The most satisfying years were 1990-91 and 1991-92, when the Penguins won successive Stanley Cups. In the 1991 playoffs, Errey played 24 games, scoring five goals and two assists as the Penguins defeated the Minnesota North Stars in the finals. They defended their championship the following year, defeating the Chicago Blackhawks.
After brief stints with the Buffalo Sabres and San Jose Sharks, Errey spent two-and-a-half years with the Detroit Red Wings where he was part of the Red Wings team that advanced to the Stanley Cup finals in 1995, only to be swept away by the New Jersey Devils. Midway through the following season, Errey was sent back to San Jose.
In 1997-98, Errey signed a free agent contract with the Dallas Stars, but after 59 games that year he was sent to the New York Rangers, where he dressed for just two games. That marked the final year of his NHL career.
Errey played one more year of pro hockey with the Hartford Wolf Pack of the AHL before retiring at the age of 34.
On August 29, 2001, Errey announced he was coming out of retirement in an attempt to rejoin the Penguins. Evidently, the return of Mario Lemieux provided the needed inspiration for more than just Michael Jordan's return to basketball. However, after several days in camp, Errey abandoned the comeback and returned to his job as color commentator on Penguins' broadcasts.