In the playoffs, Dineen had a goal, eight points, and 59 penalty minutes in 19 games as the Greyhounds lost to the Kitchener Rangers in the final round.
Following his junior career, the Islanders assigned Dineen to the Indianapolis Checkers of the Central Hockey League (CHL) for the 1982–83 season.
Dineen also saw limited action with the New York Islanders, playing in two games in the 1982–83 season and did not score any points.
Dineen played in nine playoff games, scoring a goal and two points, as the Islanders lost to the Edmonton Oilers in the 1984 Stanley Cup Finals.
In 1984–85, Dineen spent time with the Islanders American Hockey League (AHL) affiliate, the Springfield Indians.
He spent a majority of the 1984–85 season with the Islanders, playing in 48 games, scoring a goal and 13 points, as well as earning 89 penalty minutes.
His tenure with the Islanders is perhaps best known for assisting on Pat LaFontaine's series-winning goal in the fourth overtime in the 1987 Stanley Cup playoffs opening round against the Washington Capitals, known today as "The Easter Epic.
On April 3, Dineen scored his first goal with the North Stars, against Mike Vernon of the Calgary Flames, in a 4–1 loss.
The North Stars assigned Dineen to the Kalamazoo Wings of the International Hockey League (IHL) for 25 games with two goals and eight points.
On December 17, 1988, the North Stars traded Dineen and Scott Bjugstad to the Pittsburgh Penguins for Ville Siren and Steve Gotaas.
Dineen made his debut with the Pittsburgh Penguins on December 23, 1988, earning no points in a 2–2 tie against the New Jersey Devils.
On February 14, Dineen scored his first goal with Pittsburgh against Jacques Cloutier of the Buffalo Sabres and added an assist in a 7–3 win.
In 1989–90, Dineen played in 69 games with the Penguins, scoring a goal and eight points, while earning a career-high 125 penalty minutes.
In the post-season, Dineen scored two goals and six points in 14 games, as Muskegon lost to the Kansas City Blades in the Turner Cup finals.
Dineen played in his first game with Ottawa on January 21, 1993, where he was held without a point in a 7–2 loss to the Minnesota North Stars.
On February 25, Dineen scored his first goal with the Senators against Tom Barrasso of the Pittsburgh Penguins and added an assist in a 2–1 win.
Due to the 1994–95 NHL lockout, Dineen spent a majority of the season with the Islanders IHL affiliate, the Denver Grizzlies, where he was named captain of the team.
Dineen's was named as a player-coach during his final season with the Utah Grizzlies in 1999 until he was traded to the Chicago Wolves in March 2000.
After retiring from playing, Dineen was named an assistant coach with the Louisville Panthers of the American Hockey League (AHL) in 2000–01.
In 2002, Dineen became the head coach and general manager of the ECHL's Richmond Renegades, leading the team to a 35–31–6 record and 76 points.
The Grizzlies suspended operations in 2005 and Dineen was moved to the Coyotes' new AHL affiliate, the San Antonio Rampage in the same role from 2005 to 2007.
Dineen was promoted to head coach of the Marlies for the 2014–15 season,[3] earning a record of 40–27–9–0 for 89 points, finishing second in the North Division.
Dineen then joined the Rochester Americans of the AHL as an assistant to head coach Chris Taylor in 2017.