Frank Stranahan, the premier amateur golfer of his era who contended for majors and was the first notable player to make fitness a regimen in golf, died June 23 at a hospice in West Palm Beach, Fla. He was 90.

Quattlebaum Funeral Home confirmed the death but did not provide the cause.

Mr. Stranahan, who was regarded as the best amateur since Bobby Jones, won more than 50 amateur titles, including multiple wins in the British Amateur, Western Amateur and North and South Amateur.

The one title that eluded him was the U.S. Amateur. He lost in the fifth round to Arnold Palmer in the 1954 U.S. Amateur, and then turned pro. Mr. Stranahan, who packed barbells in his suitcase to work out on the road, won six times on the PGA Tour, twice as a pro. His biggest win was the 1958 Los Angeles Open.

As an amateur, he was a runner-up in the 1947 Masters to Jimmy Demaret, finished one shot behind Fred Daly at Hoylake in the 1947 British Open and was a runner-up to Ben Hogan at Carnoustie in the 1953 British Open.

In this April 21, 1949 file photo, Arnold Palmer, left, and Frank Stranahan walk together at the 49th North and South amateur golf tournament in Pinehurst, N.C. (AP)

Mr. Stranahan was devoted to fitness as much as to golf. He ran in more than 100 marathons and won trophies for bodybuilding and weightlifting well into his 70s. One video shows Mr. Stranahan celebrating his 78th birthday with a dead lift of 265 pounds.

Frank Richard Stranahan was born Aug. 5, 1922, in Toledo. His father was the founder of Champion Spark Plug, and the younger Stranahan grew up amid wealth and privilege.

He was a sportsman at the Inverness Club in Toledo, where he was taught by Byron Nelson, who had been hired as the head pro shortly before Nelson won the 1939 U.S. Open. Mr. Stranahan was still a teenager when he won the Ohio Amateur in 1941.

“I would say my greatest accomplishment as an amateur was having the opportunity to play in so many of those wonderful golf tournaments,” Mr. Stranahan told the Toledo Blade in 2011. “At every tournament, they put me with the winner from the week before. So I was always playing with Demaret, [Sam] Snead, [Bobby] Locke, Hogan and other tremendous champions. I was playing the best courses with the best players, and it was very satisfying to do well in those situations.”

He tied with Nelson in the 1947 Masters, where Mr. Stranahan closed with a 68 to finish two shots behind Demaret. His best chance at a major was at Hoylake that summer, when he went into the final round one shot behind Daly and matched his 72. Six years later, he closed with a 69 to finish in a tie for second at Carnoustie, four shots behind Hogan.

In one of the more famous tales involving Mr. Stranahan, he was not allowed to compete in the 1948 Masters when he was accused of hitting more than one shot into the greens during the practice round.

Mr. Stranahan said he was only hitting additional putts onto the green, which was allowed. No matter. He said club officials revoked his invitation.

“So I bought a ticket, and I stayed there,” Mr. Stranahan told Sports Illustrated in 1998.

He played the next year and tied for 19th.

Mr. Stranahan retired from competition in 1964, though he left quite a mark. Beyond his results, he cut an impressive figure with his movie star looks and physique that he enjoyed showing off in tight-fitting shirts. Palmer referred to him as “Muscles.”

“He used to carry his weights in a suitcase,” Palmer said. “He’d get the bellman to carry the luggage to his room, but it was so heavy they couldn’t lift it.”

Mr. Stranahan married the former Ann Williams in 1953. She became an accomplished amateur golfer before her death in 1975 from cancer. Two of their sons died, Frank Stranahan Jr. in 1966 at 11 from bone cancer and James Stranahan in 1977. Survivors include his third son, Lance Stranahan.