As a high school football player, Randy received honors including All-League, All-County, and the Star Helmet Award.

[4] In Gradishar's three years with the Buckeyes, all as a starter, the team had a 25–6–1 record, with two Big Ten Conference championships.

Gradishar's final collegiate game was a 42–21 victory over the University of Southern California in the 1974 Rose Bowl, to complete a 10–0–1 season.

"[4] Before entering the National Football League Gradishar played in the Hula Bowl and the Coaches' All-American game in 1974.

In 1999 Gradishar received the Dick Butkus Silver Anniversary Award recognizing his achievements 25 years after his graduation from Ohio State.

[14] Gradishar became nationally known in a 1975 Monday Night Football game versus the Green Bay Packers in which he picked off a pass and returned it for a game-sealing touchdown while also recording a sack, two tackles for loss and knocked down two passes and recorded six solo tackles.

[13] In addition to leading the Broncos in tackles for the second straight year, Gradishar led all NFL linebackers in sacks, with seven.

The Broncos defense allowed 198 points in 16 games, which was second in the NFL behind the Super Bowl champion Steelers.

The Broncos returned to the playoffs in 1983, led by rookie quarterback John Elway and Gradishar, as he capped off his career with his seventh Pro Bowl in ten NFL seasons.

He was the centerpiece of Joe Collier's 3-4 and the glue that held a ragtag bunch of degenerates and hand-me-downs (I mean that in a good way) together.

"[25] Pro Football Weekly's personnel scout Joel Buchsbaum wrote that "there are quite a few scouts who will tell you that former Broncos ILB Randy Gradishar was almost as good, even as good, as Jack Lambert" and "unlike Lambert, Gradishar was not a flashy headhunter, just a great anticipator who was a deadly tackler and great short-yardage defender".

[28] Pro Football Weekly published these comments collected from NFL scouts, "Superior diagnostician with exceptional strength, balance, tackling form and very good lateral mobility.

Not as flashy or brutal as some ILBs but means almost as much to Denver's defense as Walter Payton does to Chicago's offense" and "Is most dominant defender in AFC when healthy.

Although not as brutal as Butkus or Bergey, he's strong at the point of attack, does a superb job of playing off blocks and getting to the ball, gets good depth on his pass drops and is consistently excellent"[29] Zander Hollander, who wrote The Complete Handbook of Pro Football, said about Gradishar, "Not as nasty as Butkus, doesn't snarl like Lambert, but Gradishar makes all the plays.

In it, Tony Dorsett recalled the hit Gradishar gave him in a 1980 game, "I ran a pass pattern and was wide open but Danny White did not see me.

He had a great ability to square his body into the ball carrier at the moment of impact; which made him an incredible performer on third or fourth and short.

"[24] Detroit Lions General Manager and fellow inside linebacker Matt Millen added, "Randy Gradishar was one of the most productive players I've watched.

"[24] Mike Giddings of Proscout, Inc., added that "Gradishar could cover the "Y" flat on a weakside linebacker blitzed.

Additionally, coach Joe Collier would have a unique coverage on a strong-side blitz in which Gradishar, the right inside linebacker would be responsible to cover the tight end, man-to-man, on any "up" route in the "seam", which would be on the opposite side of the formation.

[24] In January 2008, he was voted by a panel of former NFL players and coaches to Pro Football Weekly's All-Time 3-4 defensive team along with Harry Carson, Lawrence Taylor, Andre Tippett, Howie Long, Lee Roy Selmon, and Curley Culp.

[30] Gradishar retired after the 1983 season, finishing his career with the NFL record for most tackles all time with 2,049, and 20 interceptions, which he returned for 335 yards and three touchdowns.

[31] After his retirement, Gradishar was nominated for the Pro Football Hall of Fame multiple times, was not enshrined until 2024.

The closest he came to induction prior to 2024 was the day before the 2003 Super Bowl, when he made it to list of final ten.

[32][33] In August 2023, Gradishar, along with Art Powell and Steve McMichael, was selected as a senior finalist to the Hall of Fame's Class of 2024.

[36] The Professional Football Researchers Association named Gradishar to the PRFA Hall of Very Good Class of 2008.