Fran O'Brien, 63, a prominent Washington restaurant owner who was a legendary Washington Redskins offensive lineman of the 1960s, died Oct. 21 at George Washington University Hospital after a heart attack.

The Vienna resident was stricken at his restaurant, Fran O'Brien's Stadium Steak House, 1001 16th St. NW.

Mr. O'Brien, who had owned and operated restaurants in Washington since 1962, played for the Redskins from 1960 through 1966. He played mainly offensive right tackle, though he could fill in at guard if needed. No. 61 was, according to a Washington Post sports columnist of the era, "known as a fine technician with tremendous strength."

He also was a beefy, tough-talking warrior who was as unlikely to walk away from an on-field rhubarb as he was to hold a grudge after the game. If he played for Redskins teams that seemed to lose far more often than they won, it was not for lack of the aggressiveness of Fran O'Brien. He once played six straight seasons without missing a game, despite a collection of injuries that would have sidelined others.

The great former Redskins quarterback Sonny Jurgensen once recalled Mr. O'Brien's tenacity, saying that if the going got truly tough, Fran O'Brien would simply illegally hold on every play. He explained to Jurgensen that no referee would dare call a penalty on every play.

Mr. O'Brien was a Massachusetts native and a 1959 education graduate of Michigan State University. After starring with the Spartans, he became the third draft choice of the Cleveland Browns, signing for a $500 advance on his salary.

He spent the 1959 season with the Browns, then in April 1960, the 6-foot-1, 240-pound tackle was traded with rookie lineman and kicker Bob Khayat to the Redskins for kicker Sam Baker. It became Mr. O'Brien's chance to play every day and to develop into a talented lineman. In Cleveland, he had played behind the legendary Lou Groza and Mike McCormack at tackle and guard.

In 1966, he was traded to Pittsburgh and retired from the Steelers in 1969 after three seasons. The Steelers of that era were even less successful than the Redskins. After leaving football, Mr. O'Brien decided to settle in Washington and devote himself to the restaurant business.

Over the years, he had interests in a variety of area restaurants and bars. They ranged from beer and pizza joints to the present posh establishment, which, according to Post reviews, features large and tasty steak and chops as well as great burgers. One review also cautioned the prospective diner not to try ordering something like a "pu-pu platter."

Over the years, Mr. O'Brien also opened and owned popular establishments in California and Florida.

His Washington restaurant has become the gathering place for sports fans in the city, a place where many of Mr. O'Brien's friends and former teammates would repair for a meal and the odd libation.

But O'Brien restaurants may not have always been as sedate as now. In 1970, a Post reporter told readers of a Wednesday night goings-on at Fran O' Brien's at 1823 L St. NW. Somehow, amid fine dining and dancing, a 16-hand gelding entered the restaurant and excitement ensued.

Mr. O'Brien's attorney assured The Post that the owner had not invited the horse into the restaurant.

In 1972, Mr. O'Brien had excitement of another kind. He went to California to see a Michigan State football game and ended up in a movie. Invited to watch the filming of "The Adjuster," the director obviously considered Mr. O'Brien a possible star. The former lineman secured a walk-on role as a detective and said his single line ("What are we, magicians?") to everyone's satisfaction--or at least the director's.

In addition to playing and following college and professional football, Mr. O'Brien was a baseball fan. It was said that after becoming a full-time businessman, he never missed a home game of the old Washington Senators until they moved to Texas in 1972.

He told one Post reporter that while defensive linemen Gino Marchetti of the Baltimore Colts and Deacon Jones of the Los Angeles Rams were the toughest opponents he ever faced, they were not as strong as his pal, the massive Senators first baseman-outfielder Frank "Hondo" Howard.

After he retired from football, Mr. O'Brien told The Post that he was looking forward to living in Washington and simply becoming a hometown fan. As for his years in football, he said, grinning: "I guess you have to have a special kind of mind, or lack of it, to be a lineman. But linemen take their frustrations out on each other. That's why they make such gentle companions. Ask me, I used to be a lineman."

His marriage to Elizabeth O'Brien ended in divorce.

Survivors include his companion, Frances Blevins, of Vienna; two children, Marty O'Brien of Washington and Elizabeth Vento of Rome; and two granddaughters.

CAPTION: Fran O'Brien was "known as a fine technician with tremendous strength," a Post columnist once wrote. Mr. O'Brien died Oct. 21 after a heart attack.