Lemaire, who retired after last season, replaced first-year coach John MacLean in December and led the Devils on a dramatic turnaround but still fell short of making the playoffs.
"I said today when I talked to my wife, if I were younger I'd come back, because I love it," the 65-year-old Lemaire told reporters after his team beat the Boston Bruins 3-2 in their final game of the regular season. "But hockey demands a lot. I want to enjoy life."
The Devils went 29-17-3 since Lemaire's return this season and climbed out from last place in the Eastern Conference but dropped out of playoff contention last week.
A Hall of Fame player and eight-times Stanley Cup winner during his playing days with the Montreal Canadiens, Lemaire leaves coaching with a career mark of 617-458-187.
He coached the Devils from 1993-98 and led the franchise to their first Stanley Cup in 1995. Lemaire first coached the Montreal Canadiens and also coached the Minnesota Wild from 2000-2009 before rejoining New Jersey.
(Writing by Jahmal Corner in Los Angeles; Editing by Frank Pingue)