Devils executive vice president and general manager Ray Shero announced the signing Tuesday.
The 30-year-old Letourneau-Leblond spent the past two seasons with Wilkes-Barre Scranton (AHL), where he played under new Devils coach John Hynes. He had two goals and four assists and finished third in the AHL in penalty minutes during each of his two seasons with the Penguins.
His last NHL appearance came on Jan. 15, 2014, against Washington, marking his only game played with Pittsburgh.
The Quebec native was drafted by the Devils in 2004. He had three assists in 37 NHL games with New Jersey in his six seasons with the organization.