. NEW YORK (AP) — President John F. Kennedy had just one critique when he saw photos of the actor set to play him in a World War II drama.

Associated Press
Cliff Robertson in 1966.
The year was 1963 and actor Cliff Robertson looked convincing in his costume for "PT-109," the first film to portray a sitting president. Kennedy had favored Robertson for the role, but one detail was off.

Robertson's hair was parted on the wrong side.

The actor dutifully trained his locks to part on the left and won praise for a role he'd remain proud of throughout his life.

Robertson, who went on to win an Oscar for his portrayal of a mentally disabled man in "Charly", died of natural causes Saturday afternoon in Stony Brook, a day after his 88th birthday, according to Evelyn Christel, his secretary of 53 years.

Robertson never elevated into the top ranks of leading men, but he remained a popular actor from the mid-1950s into the following century. His later roles included kindly Uncle Ben in the "Spider-Man" movies.

He also gained attention for his second marriage to actress and heiress Dina Merrill, daughter of financier E.F. Hutton and Marjorie Merriweather Post, heiress to the Post cereal fortune and one of the world's richest women.

His triumph came in 1968 with his Academy Award performance in "Charly," as a mentally disabled man who undergoes medical treatment that makes him a genius — until a poignant regression to his former state.

"My father was a loving father, devoted friend, dedicated professional and honorable man," daughter Stephanie Saunders said in a statement. "He stood by his family, friends, and colleagues through good times and bad. He made a difference in all our lives and made our world a better place. We will all miss him terribly."

Robertson had created a string of impressive performances in television and on Broadway, but always saw his role played in films by bigger names. His TV performances in "Days of Wine and Roses" and "The Hustler," for example, were filmed with Jack Lemmon and Paul Newman, respectively. Robertson's role in Tennessee Williams' play "Orpheus Descending" was awarded to Marlon Brando in the movie.

Robertson first appeared in the "Charly" story in a TV version, "The Two Worlds of Charlie Gordon." Both were based on "Flowers for Algernon," a short story that author Daniel Keyes later revised into a novel. Robertson was determined that this time the big-screen role would not go to another actor.

"I bought the movie rights to the show, and I tried for eight years to persuade a studio to make it," he said in 1968. "Finally I found a new company, ABC Films. I owned 50 percent of the gross, but I gave half of it to Ralph Nelson to direct."

Critic Roger Ebert called Robertson's portrayal "a sensitive, believable one." The motion picture academy agreed, though Robertson was unable to get a break from an overseas movie shoot and was not on hand when his Oscar was announced.

Portraying Kennedy in "PT-109," presented other challenges. The president warned Robertson he didn't want someone trying to imitate his distinctive New England accent.

"That was fine with me," the actor commented in 1963. "I think it would have been a mistake for me to say 'Hahvahd' or try to reproduce gestures. Then the audience would have been constantly aware that an actor was impersonating the president."

He added that the film obviously couldn't be done with heroics, "like Errol Flynn gunning down 30 of the enemy. This young naval officer just does things because they have to be done."

"PT-109" was plagued with problems from the start: script changes, switch of directors, bad weather, snakes and mosquitoes in the Florida Keys where it was filmed.

The troubles were evident on the screen, and critics roundly rapped the film, although Robertson's work won praise.

In 1977, Robertson made the headlines again, this time by blowing the whistle on a Hollywood financial scandal.