Crenna, who suffered from pancreatic cancer, died of heart failure Friday at Cedars-Sinai Medical Center, his family at his side, CNN reported.
Crenna began a virtually non-stop career that lasted more than 60 years as a squeaky-voiced 10-year-old on the radio and moved through a remarkable variety of roles in television and the movies, including the "Rambo" films.
Most recently, Crenna played Jared Duff on the TV series "Judging Amy." In 2001, he played President Reagan in a television movie, "The Day Reagan Was Shot."
He worked much more than most Hollywood actors, appearing in so many shows and movies that he often forgot he had acted with some of the profession's most famous stars.
"I've done so many things I can't remember or begin to count them," he told United Press International in 1993. "The other night the movie 'Star' was rerun on a cable show. I'd completely forgotten I was in it with Julie Andrews. I sat there like an audience and watched," he said.
Crenna's pre-adolescent voice was heard on radio's "A Date With Judy," "The Great Gildersleeve" and "Our Miss Brooks," in which he traveled with star Eve Arden to television portraying the somewhat dimwitted high school student Walter Denton.
He did six other TV series, including 237 episodes of "The Real McCoys" with Walter Brennan from 1957-63. He also directed more than 300 TV shows, including episodes of the "The Rockford Files," "The Andy Griffith Show," and "Lou Grant."
His first movie was "The Pride of St. Louis," and his films included "The Sand Pebbles," "Body Heat," "The Flamingo Kid," and the several Rambo movies in which he played Sylvester Stallone's former commanding officer.
In the 1993 action movie parody, "Hot Shots! Part Deux," Crenna did a takeoff on his Col. Troutman character of the Rambo series, playing Col. Denton Walters, a turnaround of his "Our Miss Brooks" character's name.
In addition to the wealth he accumulated as an actor, Crenna also collected rare coins from childhood and his collection was reputedly worth a fortune.
Crenna was honored with a star on the Hollywood Walk of Fame in 1988.
He is survived by daughters Seanna and Maria, son Richard and his wife, Penni.