Comeau began his NLL coaching career with the Toronto Rock, as an assistant coach under the legendary Les Bartley. The Rock won four NLL Championships under Bartley (1999, 2000, 2002, and 2003 NLL season).
In November 2003, Bartley stepped down due to his battle with colon cancer, and Comeau was promoted to interim head coach. However, less than four months later, after a 2-4 start, both Comeau and interim GM Derek Keenan were fired by the Rock, replaced by Terry Sanderson.
In 2004, Comeau joined the Rochester Knighthawks as an assistant coach, and was then promoted to head coach at the beginning of the 2006 season, replacing Paul Day. Rochester finished with a 9-7 record, second in the Eastern division, but were eliminated from the playoffs by the Buffalo Bandits in the division finals.
In 2007, the Knighthawks began the season 2-2, and then won a franchise record 12 straight games to finish the season with a 14-2 mark, tied for the best record since the NLL went to a 16-game schedule. They continued the winning streak in the postseason, defeating Toronto, Buffalo, and finally Arizona to win their first championship since 1997. After the season, Comeau was named the winner of the Les Bartley Award for coach of the year.
After a disappointing 2008 season in which the Knighthawks missed the playoffs for the first time in franchise history, Comeau announced that he would not be returning to the Knighthawks. Only three days later, Comeau was announced as the new head coach of the New York Titans, after former coach Adam Mueller announced his retirement.
- "Les Bartley sidelined by cancer". Outsider's Guide to the NLL. 2003-11-05. Archived from the original on 2007-08-18. Retrieved 2007-05-24.
- "Rock cans Ed Comeau, Derek Keenan". Outsider's Guide to the NLL. 2004-02-17. Archived from the original on 2007-08-18. Retrieved 2006-11-08.
- "K'hawks' Comeau named Coach of the Year". TSN.ca. May 3, 2007.
- "Ed Comeau Wins Les Bartley Award". NLL.com. May 3, 2007. Retrieved 2007-05-24.
- "Comeau Will Not Return To K-hawks in 2009". NLL.com. June 26, 2008. Retrieved 2008-07-14.
- "Mueller Retired; Comeau Hired In New York". NLL.com. June 30, 2008. Retrieved 2008-07-14.
| Les Bartley Award
| NLL GM of the Year