The 43-year-old DeBoer spent the past three seasons as the coach of the Florida Panthers. He was fired after failing to lead the team to the playoffs during his tenure.
DeBoer succeeds Jacques Lemaire, who came out of retirement in midseason after rookie coach John MacLean was fired in December. However, Lemaire's return could not prevent the Devils from missing the playoffs for the first time since 1996.
The coaching change is the ninth for the Devils since the late Pat Burns stepped down after being diagnosed with cancer in 2005.
DeBoer posted a 103-107-36 record with the Panthers.
"Peter DeBoer is an individual who I have watched coach over the past two decades at the junior, international, and professional levels," Devils president Lou Lamoriello said. "His teams have always been well-prepared and disciplined, while maximizing their effort each and every night.
"I am looking forward to working with him."
DeBoer led the Panthers to the second-best finish in franchise history in 2008-09. They won 43 games that season, and posted 93 points.
DeBoer has served as a head coach for 16 consecutive seasons, including 13 years in the Ontario Hockey League with Kitchener (2001-08), Plymouth (1997-2001), and Detroit (1995-97). In seven seasons with the OHL Rangers, he posted 297 wins, a .676 winning percentage, and led the club to the 2003 Memorial Cup Championship and the 2008 OHL Championship.
He is a native of Dunnville, Ontario.
The Devils, who won three Stanley Cup titles from 1995-2003, have not been past the second round since.