Greene was 58. No cause of death was given.
The Pro Football Hall of Fame said Greene, a star at linebacker and defensive end during a 15-year career, died at his home in Florida.
“We lost an amazing player and person this morning with the passing of Kevin Greene,” Steelers president Art Rooney II said in a statement. “His sudden death is a shock to us all as he was a close friend and teammate to so many people in the Steelers family.
“When Kevin came to the Steelers in 1993 (after eight seasons with the Rams) he had an immediate impact. Paired with Greg Lloyd, Kevin and Greg led a defense that became known as Blitzburgh and went on to play in Super Bowl XXX,” Rooney said. “Kevin’s energy and enthusiasm were inspiring for our team as well as our fans.”
A walk-on at Auburn University, Greene was a fifth-round draft pick of the Los Angeles Rams in the 1985 NFL draft and went on to play for the Rams, Steelers, Carolina Panthers and San Francisco 49ers. He played in 228 games, was named to the Pro Bowl five times and is part of the NFL’s All-Decade team of the 1990s. He led the league in sacks twice, in 1994 and 1996 when each time he was an All-Pro.
His 160 sacks are third since the NFL began compiling the statistic in 1982.
“I loved getting a sack,” Greene said, according to the Pro Football Hall of Fame website. “My teammates depended on me to do that. I contributed. I didn’t want to let my teammates down … (It) was just me making a contribution and not letting my brothers down.”
While with the Steelers, Greene played in six conference championship games and one Super Bowl.
“I believed in my heart that I was unblockable, and it was a phenomenal experience,” Greene said of his time with Pittsburgh, according to the Pro Football Hall of Fame website.
Greene helped the Panthers reach the NFC title game in 1996. He retired after the 1999 season and was elected to the Pro Football Hall of Fame in 2016.
“Our thoughts and prayers are with Kevin’s wife, Tara, and their entire family. We will forever keep his legacy alive to serve as inspiration for future generations. The Hall of Fame flag will be flown at half-staff in Kevin’s memory.”
CNN’s Steve Almasy contributed to this report.