HOUSTON -- Longtime NFL coach Romeo Crennel announced his retirement on Monday after 50 years of coaching.

Crennel, 74, coached 39 seasons in the NFL, including as the head coach of the Cleveland Browns and Kansas City Chiefs. He also served as the Houston Texans' interim head coach in 2020.

That season, at 73 Crennel became the oldest person in NFL history to serve as a head coach in a game, a record previously held by former Chicago Bears head coach/owner and NFL co-founder George Halas. Crennel finished his career with a 32-63 record as a head coach.

"Football has been my entire life and it's been a dream come true to coach for 50 years," Crennel said in a statement. "...I'll miss everything about coaching and teaching, but the thing I'll miss the most is being around the guys every day. My goal was to put every player and coach in the best position to succeed, and I consider every guy I coached or worked with a part of my family."

Among his former players, J.J. Watt, who played seven seasons for Crennel in Houston, took to Twitter to express high praise for the coach.

Absolute legend of the game and even better man. https://t.co/eaHtpAmFTE

— JJ Watt (@JJWatt) June 6, 2022

Crennel spent his last eight years in the NFL with the Texans. During the 2021 season, Crennel was Houston's senior adviser for football performance.

In 2020, the Pro Football Writers of America awarded Crennel with the 2020 Paul "Dr. Z" Zimmerman Award for lifetime achievement as an assistant coach.

"My family and the entire Houston Texans organization would like to congratulate Romeo Crennel on his historic coaching career," Texans chair and CEO Cal McNair said in a statement. "After 50 seasons, Romeo retires as one of the most respected figures in NFL history. His incredible resume and contributions to the game of football will be difficult to duplicate.

"Our organization is better because of Romeo Crennel in so many ways. He will always be a Texan and we wish him, his wife Rosemary and his family nothing but the best in all that retirement brings."