Three-time Pro Bowl linebacker who played his entire NFL career with the Dallas Cowboys and finished his career as the team's second-leading tackler.
He played college football at Arizona State University, where he was a two-time captain and was inducted into their Hall of Fame in 2012.
He expected to be drafted in the first round of the NFL draft but wasn't taken until the third round, which he said motivated him to work harder and prove his abilities.
He raised his family in Lake Highlands in Dallas, Texas.
He played alongside Hall-of-Fame quarterback Roger Staubach in Dallas.