In this 1975 photo, Baltimore Colts wide receiver Roger Carr scampers past Pittsburgh Steelers defensive end L.C. Greenwood (68) during a football game in Pittsburgh. Greenwood, who won four Super Bowls as a member of the "Steel Curtain" defense, died Sept. 29. He was 67. (Anonymous/AP)

L.C. Greenwood, the relentless defensive end who made up one quarter of the Pittsburgh Steelers’ “Steel Curtain” defense of the 1970s, died Sept. 29 at a hospital in Pittsburgh. He was 67.

The Allegheny County Medical Examiner’s office confirmed the death but did not state the cause.

A six-time Pro Bowler and two-time all-pro, Mr. Greenwood played for the Steelers from 1969 to 1981, helping Pittsburgh win an unprecedented four Super Bowls in a six-year span. Mr. Greenwood, Joe Greene, Ernie Holmes and Dwight White formed the bedrock of the defense that helped turn a perennial loser into a dynasty.

Mr. Greenwood was taken in the 10th round of the 1969 NFL draft out of Arkansas A&M (now University of Arkansas at Pine Bluff). He blossomed into a tenacious pass rusher who used his superior speed to blow past offensive tackles and into the backfield. Though sacks did not become an official statistic until after his retirement, Mr. Greenwood was credited with 73½ sacks during his 13-year career.

In the 1976 Super Bowl, he sacked Dallas Cowboys quarterback Roger Staubach four times during a 21-17 Pittsburgh victory.

Unlike his quieter teammates, Mr. Greenwood could be a showman. He sometimes wore a pair of flashy high-top cleats painted gold.

Knee problems forced Mr. Greenwood to retire before the 1982 season. He remained in Pittsburgh after his retirement, working as an entrepreneur and motivational speaker.

Despite support from his teammates — including Greene — Mr. Greenwood has not been enshrined in the Pro Football Hall of Fame. He was a finalist six times, the last time in 2006.

— Associated Press