Over three-plus seasons, DeBoer led the Devils to a 114-93-41 record.
The 46-year-old led New Jersey to the Stanley Cup finals in 2012, but the team did not make the playoffs in two subsequent seasons.
New Jersey opened this season 12-17-7, the third-worst mark in the Eastern Conference and good for seventh place in the Metropolitan division.
Prior to becoming the bench boss of the Devils, DeBoer coached the Florida Panthers for three seasons.
New Jersey faces the Rangers in New York on Saturday.