John Mitchell, after 29 years with the Pittsburgh Steelers, is calling it a career. 

The Steelers' longest-tenured coach, Mitchell served as the team's defensive line coach from 1994-2017. He split his duties there along with being named the team's assistant head coach when Mike Tomlin became the Steelers' head coach in 2007. Mitchell has been the team's full-time assistant head coach since 2018. 

"I'm grateful to the Rooney family for the wonderful opportunity to coach and work for the Steelers for nearly 30 years," Mitchell told the team's website. "It was truly an honor. I'd also like to thank Coach Tomlin for giving me the opportunity to stay with the franchise when Coach Cowher retired. I will treasure my time in Pittsburgh and appreciate everyone affiliated with the organization."

A football player himself, Mitchell broke the color barrier at Alabama before starting his coaching career at his alma mater in 1973. He spent nearly two full decades at the college ranks before Bill Belichick hired him to coach the Browns' defensive line in 1991. He spent three years in Cleveland before coming to Pittsburgh, where he won two Super Bowls and three AFC titles. 

"I'm not sure that I can offer sufficient praise and admiration for Mitch -- as both a man and football coach," Tomlin said. "Mitch has been a central figure in the success of the Pittsburgh Steelers for nearly three decades. He has coached some of the best players in this franchise's illustrious history, and each one of them, to a man, would tell you their success was a direct result of not only Mitch's coaching acumen, but also his mentorship, leadership and character.

"Those traits were most evident when he chose to attend the University of Alabama. Mitch's path not only changed his life, but the lives of so many others. It's impossible to truly measure his impact on the game, but I'm eternally grateful for the 16 years we worked together and wish him and (his wife) Joyce the absolute best in retirement."

Mitchell coached several standout defensive linemen during his time with the Steelers. Those players include Cameron Heyward, Casey Hampton, Aaron Smith, Brett Keisel, Joel Steed, Stephon Tuitt, and Tyson Alualu, among others. 

Pittsburgh's defense immediately began to excel once Mitchell arrived. The Steelers were second in scoring defense during Mitchell's first season. That was the season when "Blitzburgh" became the defense's new nickname while ushering in a new era. The Steelers went to the Super Bowl the following season, where Mitchell's unit played a key hand in holding NFL career rushing leader Emmitt Smith to just 49 yards rushing in Super Bowl XXX. 

Smith's units continued to play integral roles in successful Steelers teams over the years. The Steelers won Super Bowls XL and XLIII and made it to Super Bowl XLV largely on the strength of their pass rush and run defense. 

Mitchell, 71, retires as not only a two-time Super Bowl champion but as a pioneer who helped open doors for those who came after him. 

"Coach Mitch has been a pivotal member of the Steelers organization, in a variety of roles, for the better part of 30 years," said Steelers president Art Rooney II. "When you consider his path, as both a player and coach, Mitch created opportunities in football for young Black men that quite honestly didn't previously exist. He has left an imprint on this franchise, and the sport and culture of football, that will continue well beyond his retirement."