Information on the duration of Keefe's Devils contract was provided by insider Darren Dreger.
Sounds like 4 years total including the two years owed by the Leafs.
Insider Pierre LeBrun shed light on Keefe's implications from this.
Devils expected to make the Sheldon Keefe hire official tomorrow. Keefe had a two-year extension kicking in with the Leafs next season but the Devils ripped that up and signed him to a fresh four-year deal (hint, got a raise over what the 2-year extension would have paid).
In addition to receiving a higher salary, Keefe will now be coaching a team with less media attention than Toronto. With their youthful core, Keefe will try to guide the Devils on a lengthy playoff run; we're still awaiting an official statement from the team.