He played ten seasons in the NHL between 1973 and 1983 with the Boston Bruins, Hartford Whalers, Los Angeles Kings.

With the team returning to the CHL after the IHL dissolved, it was eliminated in the second round of the 2010-11 postseason before winning the league in 2011–12.

However, the Komets failed to make the postseason in 2012–13, with the team in the ECHL, his final season as their head coach.

The team was declared dormant in 2016–17 in preparation for moving elsewhere, which turned out to be Jacksonville, Florida in 2017–18, and a new head coach took over.

Sims' son Tyler was the starting goaltender of the Providence College Friars in Hockey East (2004 to 2008), and a reserve goalie for several minor league teams (2007 to 2011).