While with the Bruins he appeared in his first two NHL games during the 2005–06 season, collecting no points and seven penalty minutes.

Leach spent most of his time in the Bruins organization with their AHL affiliate in Providence.

He began the 2010–11 season playing for the AHL's Worcester Sharks, but on February 9, 2011, he was traded back to the New Jersey Devils along with Steven Zalewski in exchange for Patrick Davis and Mike Swift.

[2] Leach became an assistant coach with Adler Mannheim of the Deutsche Eishockey Liga in 2014, helping the team in winning their sixth DEL Championship.

[6][7] Leach departed the Penguins after one season, eventually joining the Providence Bruins as an assistant coach on August 4, 2016.