"I am stepping away from the NFL at this time in order to spend more time with my wife, Tara, and our children, Gavin and Gabrielle," Greene said in a statement released by the Packers. "I will miss coaching and will try to return after our kids move on to college if a team will have me.
"My experience here with the Green Bay Packers has been nothing but positive. I am eternally grateful for the opportunity that Mike McCarthy and Ted Thompson have blessed me with. I have a peace about the productivity that I helped bring forward in all of the fine young men that have been entrusted to me these past five years. I am most proud of all their accomplishments and the fine young men they've become in this league."
McCarthy made the announcement Friday afternoon.
Greene has been with the Packers for the past five seasons, beginning with the rookie year of star outside linebacker Clay Matthews. The fiery, intense coach showed absolutely no signs that he was considering making such a decision.
"Kevin approached me recently to express his desire to step away from coaching so that he could spend more time with his family," McCarthy said in a statement. "On behalf of the entire organization, I want to thank him for all of his contributions and hard work over the past five seasons with the Packers.
"Kevin provided an incredible amount of energy, passion and knowledge each and every day he was with us. The dedication he showed to maximizing the potential of his players was clearly evident to anyone that worked with him, and he will be missed. I want to wish Kevin, Tara, Gavin and Gabrielle nothing but the best in the years ahead."
The Packers will now search for a new outside linebackers coach, while also continuing their attempts to replace former quarterbacks coach Ben McAdoo, who joined the New York Giants this week as offensive coordinator.
From his NFL playing career that included 160 sacks, Greene is a finalist for the Pro Football Hall of Fame class of 2014. He had been a semifinalist in the previous seven years.