After playing with the St. Mike's Buzzers in Toronto (Junior B), Dineen was selected the third round of the 1982 National Hockey League entry draft by the now defunct Hartford Whalers. He then played two seasons for the University of Denver Pioneers, where he was named captain in only his sophomore season. Following the 1983–83 Denver season, Kevin joined the Canadian Olympic program, and played at 1984 Winter Olympics for Canada in Sarajevo, Yugoslavia. He finished out the 1983–84 season with Binghamton in the AHL, farm club of the Hartford Whalers.
On December 3, 1984, Dineen debuted with the Whalers against the Montreal Canadiens. He completed his rookie NHL season with 25 goals. Throughout the 1980s, Dineen was a key offensive contributor for the Whalers, particularly in the 1986–1987 season, leading the team with 40 goals. In that same season, Dineen represented the NHL in the Rendez-Vous '87 series against the Soviet Union's best players.
In the 1987–1988 season, Dineen led the team with 25 goals and played in his first all-star game. On November 13, 1991, Dineen was traded to the Philadelphia Flyers, playing for his father, Bill Dineen through 1992–1993. In 1993–1994, Dineen was named team captain. In the shortened 1994–1995 season, Dineen was a runner-up for the Masterton Trophy. Midway through the 1995–1996 season, Dineen was traded back to the Whalers. On April 13, 1997, the Whalers played their last game and Dineen scored the team's final goal ever in a 2–1 victory against the Tampa Bay Lightning.
After the Whalers relocated to North Carolina in 1997–1998, Dineen continued to play for the team, now known as the Carolina Hurricanes. From 1996 until 1998, Dineen served as the team captain. In the 1999–2000 season, Dineen signed as a free-agent with the Ottawa Senators and was then selected by the Columbus Blue Jackets in the 2000 NHL Expansion Draft after only one season as a Senator. Dineen played two more seasons with the Blue Jackets and then decided to retire from the NHL after four games of the 2002–2003 season.
He completed his career with 355 goals, 405 assists, 760 points and 2229 penalty minutes in 1188 regular season games. He is notably one of only five players to score more than 350 goals while spending 2000 minutes in the penalty box. On January 6, 2006, Kevin Dineen had his Whalers number 11 honored by the AHL Hartford Wolf Pack alongside former Whalers teammates Ron Francis and Ulf Samuelsson. The ceremony took place before his Portland Pirates played against the Wolf Pack in an AHL match.
