The 41-year-old Jagr played for the Dallas Stars and the Boston Bruins last season, scoring 16 goals and handing out 19 assists in 45 games.
Jagr helped the Bruins reach the Stanley Cup Finals, recording 10 assists in 22 playoff games.
Jagr helps the Devils fill a void that was created when winger Ilya Kovalchuk decided to retire from the NHL to go play hockey in his homeland of Russia.
Jagr has 681 goals and 1,007 assists through 19 NHL seasons.
Copyright 2013 ABC News Radio
Madison Park, Keith Allen and Andreas Preuss, CNN