A 6–3, 250 pound linebacker who ran the 40-yard dash in 4.57 seconds,[7] assistant coach Merv Johnson called Traylor a "tremendous physical specimen," and an "exciting, high-profile recruit."
He was a first-team All-Lone Star Conference selection as a senior when he posted 79 tackles, five sacks, two interceptions and two fumble recoveries.
His first start of NFL career came against the Seattle Seahawks on September 15, 1991, when he opened at an inside linebacker spot in place of the injured Michael Brooks.
The first sack of his professional career occurred against the Seahawks on December 20, when he tackled quarterback Stan Gelbaugh for a 14-yard loss.
He signed with the Green Bay Packers on September 14 and played in five games with the team, all in a reserve role.
He was re-signed by the Chiefs in May 1994, but was released by the team on August 28 during final cutdowns and spent the entire season out of football.
Playing in the World League of American Football (now NFL Europa) Traylor began to add mass to his linebacker's body for a move to the defensive line.
He had a season-high six tackles against the Pittsburgh Steelers on Monday Night Football, while his lone sack of the season occurred against the Detroit Lions.
Traylor also started all four playoff games following the season, registering 11 tackles, a sack and two passes defensed.
He posted two tackles against the Green Bay Packers on January 25, 1998, as his team won Super Bowl XXXII.
Starting 14 of the 15 games in which he played with the Broncos in 1998, Traylor registered 49 tackles, two sacks, a fumble recovery and two passes defensed.
Traylor started each of Denver's three playoff games, including the team's Super Bowl XXXIII victory over the Atlanta Falcons in Miami, Florida.
His lone full sack of the season came against the Detroit Lions, while he forced fumbles against the Jacksonville Jaguars and San Diego Chargers.
He was part of a defensive unit that ranked second in the NFL, allowing an average of only 82.1 yards rushing per game.
[12] He started the team's Divisional Playoff game against the Philadelphia Eagles and was credited with four tackles and a pass defended.
Traylor entered the 2003 season in a battle with Bryan Robinson for a starting position on the Bear's defensive line.
[15] He posted 33 tackles on the year and was part of a unit that ranked sixth in the NFL in rush defense, allowing an average of only 98.3 yards per game.
Traylor joined the Miami Dolphins in 2005, as the team needed a nose tackle after then-head coach Nick Saban began to implement a hybrid defense that used the 3–4 on occasion.
He was part of a defensive line that allowed a 3.7-yard average per rush attempt, a figure that ranked fourth in the AFC and seventh in the NFL.
It was previously believed that Fred Evans was the favorite to replace Traylor at nose tackle in 2007 before the veteran re-signed.
After a confrontation with teammate Vernon Carey before the final game of the 2007 season, Traylor was kicked off the Dolphins by then-coach Cam Cameron.
[19][20] Mark Traylor died after suffering several years from Behçet's disease, a rare immune disorder.