NMU Athletic Director Forrest Karr made the announcement Friday afternoon.
He says that a comprehensive national search for the third head coach in program history will begin immediately.
"Walt has played a major role in the most significant moments in Northern Michigan hockey history," Karr said. "I enjoyed working with him, and I am thankful that he always supported every program in the department. I appreciate his work and dedication to the hockey program and wish him well in all future endeavors."
Kyle spoke with RRN's Dave Danis on Friday.
"I'm certainly not going to harbor any bitterness over this," Kyle said. "I've had a real good run here. I've been real pleased with my time here. I've been really fortunate to have the opportunity to coach at the university that I love, and the university that I, my children, and my wife graduated from. I've been lucky to coach in the hockey program where I played, and where I cut my teeth as a young coach."
Kyle compiled an overall record of 265-263-68 during 15 seasons.
He guided the Wildcats to six 20-win seasons and to the 2010 NCAA Tournament. He also coached two Hobey Baker finalists and five All-Americans.
"I look forward to the next chapter in my life," Kyle said. "People know that I will always be there to support Wildcat hockey and I'm excited to see this thing move forward and anxious to get on with whatever I'm going to do next."
Click the AUDIO button above to listen to the full interview.
Kyle played two seasons at Northern Michigan after transferring from Boston College and recorded 90 points (31g-59a) in 85 career games. He captained the 1980 and 1981 Wildcat teams that advanced to the NCAA Frozen Four.
After graduating from Northern Michigan in 1981 with a bachelor's degree in physical education, Kyle became a graduate assistant coach under Rick Comley. He was promoted to assistant coach in 1982 and held that position until 1992. He was the top assistant coach when the Wildcats won the 1991 NCAA Division I national title.