By Stephen M. Silverman
Updated January 20, 2003 11:33 AM

Veteran actor Richard Crenna, 76, who graduated from playing gawky teenagers on TV in the ’50s to leading men roles in ’60s movies — and who really never stopped working in either medium — died of heart failure Friday at Los Angeles’s Cedars-Sinai Medical Center, say reports.

The actor had been suffering from pancreatic cancer, which apparently struck around last Thanksgiving, his daughter, Seana Crenna, told The New York Times.

Crenna, a Los Angeles native, actually began his career in the late ’40s, doing squeaky-voiced youngster roles. Baby boomers remember him as the slack-jawed, gum-chewing student with the raging hormones, Walter Denton, on the popular 1952-56 sitcom “Our Miss Brooks,” starring Eve Arden as his schoolteacher, Constance Brooks.

The CBS show was produced by Desilu, which was owned by Lucille Ball and Desi Arnaz, who also cast the young actor as a lovesick teen with a crush on Lucy Ricardo for an episode that ran during the very first season of “I Love Lucy.”

From 1957 through 1963 Crenna played hunky rural husband Luke McCoy on the ABC sitcom “The Real McCoys,” which also starred Walter Brennan as the cantankerous Amos McCoy.

Yet by the late ’60s, Crenna made the leap from small screen to big, playing a vicious bully (to Audrey Hepburn) in 1967’s “Wait Until Dark,” and an astronaut in “Marooned,” about a doomed space mission.

Perhaps his most widely seen effort was when he played Colonel Samuel Trautman in the 1980s “Rambo” movie series, with Sylvester Stallone, a cartoon of a role that nonetheless left him laughing all the way to the bank.

Crenna’s most recent role was back on TV, as Tyne Daly’s love interest on CBS’s “Judging Amy.”

“He had such a full career,” said his daughter, “because he lived for his work.”

Besides Seana, Crenna is survived by his wife (since 1959) Penni; son Richard, daughter Maria and three granddaughters.