Los Angeles, California (CNN) -- Hall of Fame football player and actor Merlin Olsen, a giant man who friends say had an even larger heart, died Thursday after a long battle with cancer, football and university officials said.

He was 69.

Known as much for his brain as his brawn, the 6-foot-5, 270-pound defensive tackle also graduated summa cum laude and Phi Kappa Phi from Utah State University in 1962 and earned a master's degree in economics in the off-season during his 15-year professional career.

"Merlin Olsen was a coach's player. Punctual, steady, gifted, a quiet leader, a player you could always count on," says his biography on the National Football League Hall of Fame Web site. "He was a standout as a rookie and thereafter stood out in every game he played for the Rams in a 15-year career. Every game. Fifteen years."

There may be no better evidence of Olsen's strength than his feat of playing in 208 professional games, the last 198 in a row.

At Utah State University from 1959-1961, Olsen earned All-American honors during his junior and senior years. As a senior, he won the 1961 Outland Trophy as the nation's outstanding interior defensive lineman.

After being drafted by the Rams with a No. 1 pick in 1962, Olsen was voted into the Pro Bowl as a rookie, the first of his 14 Pro Bowl appearances. He also made two All-Decade teams and was a six-time All-Pro.

Olsen was inducted into the Pro Football Hall of Fame in 1982, his first year of eligibility.

He accomplished all those feats while playing for a sometimes less-than-stellar Los Angeles Rams team before its move to St. Louis in 1995.

"It was Olsen's hard luck to perform for many mediocre teams in Los Angeles -- he never won a Super Bowl -- but he had as much to do as any other individual with glamorizing defensive football in the NFL," his NFL biography says.

For many years, Olsen was a member of the Rams' renowned "Fearsome Foursome" defensive line that included Deacon Jones, Roosevelt Grier and Lamar Lundy.

After his professional playing career ended in 1976, Olsen turned to acting, appearing in movies and more than 100 TV episodes. He also worked as a television sports commentator.

On TV, he may best be remembered for portraying the gentle Jonathan Garvey opposite Michael Landon on "Little House on the Prairie" from 1977 to 1981 and the lead role in "Father Murphy" from 1981 to 1983.

In addition, Olsen did voice-overs in commercials for the floral delivery company FTD as well as commercials for syndicated airings of "The X-Files" TV program.

He was remembered Thursday for his character and how he excelled in so many endeavors.

"I can't think of anyone who has graduated from Utah State University who has accomplished more in a broader array of fields than Merlin Olsen," said Utah State University President Stan Albrecht. "His distinctive and powerful voice will be remembered for the breadth of its influence and by the impact it has had in so many different facets of our lives."

The university also said Olsen will be recalled "as a tireless philanthropist, giving enormous amounts of time, talent and financial resources to numerous causes across the country."

As a broadcaster, Olsen was partnered for years at NBC Sports with Dick Enberg, who recently described him as "the complete man."

In a letter to Olsen, Utah State revealed Thursday, Enberg lauded Olsen's commitment to their weekly NFL telecasts.

Enberg wrote of his partner's "uncommon willingness to prepare."

"I'd often feel that I had given an 'A' effort in our broadcasts, only to recognize you earned the 'A-plus,' " Enberg wrote.

Enberg said he also was struck by Olsen's inner self -- "a man of goodness, eager to consciously do the right thing for yourself, while helping others."

Carroll Rosenbloom, owner of the Rams during Olsen's playing days, also spoke to Olsen's unblemished character.

SI Vault: Read about Merlin Olsen's start in show business after 15 seasons with the Rams

"The thing about him that I find remarkable is never once have I ever heard him say a negative word about anybody, in any circumstance," Rosenbloom said. "I just remember having a lot of admiration and respect for him, because he was a unique guy on the team, just the kind of person he is -- gentle and wonderful, and treated everybody so well."

Rosenbloom's son Chip, majority owner of the St. Louis Rams, said Olsen will never be forgotten in team history. The Rams last honored him at a December 20 game in St. Louis.

"In Rams history, there are maybe 10 guys who are iconic, and he's one of them," Rosenbloom said. "There's nobody who is more important."

Olsen's alma mater likewise honored him in December, announcing at a basketball game half-time ceremony the naming of Merlin Olsen Field at Romney Stadium, a statue on the facility's southeast plaza and a scholarship endowment.