Cliff Robertson, who died of natural causes on Saturday, a day after his 88th birthday, won a best-actor Oscar for “Charly,” receded from Hollywood in the wake of the David Begelman-Columbia scandal but saw his profile rise at age 79, thanks to a small but important role in the first “Spider-Man” pic.

Classically handsome, Robertson was usually better than his film roles, and he proved that by winning the Oscar in 1968 for “Charly,” in which he played a retarded man who achieves temporary mental brilliance after an experimental operation.

Robertson had played the role on television and secured the rights to make sure he would star in the feature as well.

The Oscar brought him the visibility he had worked so hard to achieve after almost two decades in theater, television and films.

But the actor felt his career was adversely impacted in the wake of the 1977 Begelman check fraud scandal. Begelman, then head of Columbia Pictures, forged a $10,000 check made out to Robertson and cashed it. Robertson’s whistleblowing brought him into collision with Hollywood’s old-boy network, of whom Begelman was a member in good standing.

In addition to “Charly,” he will be remembered as the man President John F. Kennedy hand-picked to play him in the film version of “PT 109,” an account of Kennedy’s WWII exploits.

Other high points included the features “Picnic” and “The Best Man” (the TV version of “Days of Wine and Roses”) and his 1966 Emmy-winning performance in “The Game,” an episode of “Bob Hope Presents the Chrysler Theatre.”

Though Clifford Parker Robertson III was born into wealth in LaJolla, Calif., he was raised by his maternal grandfather, his parents having divorced soon after he was born. His mother died when he was a toddler.

After attending Antioch College and working at the nearby Springfield, Ohio, newspaper and radio station, Robertson decided on an acting career. Upon graduation, however, he tried to enlist in the armed forces only to be turned away because of a problem with his vision. He ended up in the Merchant Marines for the remainder of WWII.

After the war he moved to New York and tried to land an agent. He worked several odd jobs and toured with the Stanley Woolf Players, working the Borscht Belt in stock dramas. In 1948 he landed a role in the Chicago company of “Mister Roberts” and toured with it for the better part of two years. More theater work ensued, none of it particularly distinguished.

After Robertson appeared in “The Wisteria Trees,” Joshua Logan’s adaptation of Anton Chekhov’s “The Cherry Orchard,” in 1953, the director cast him in a supporting role in the film version of “Picnic.”

In 1957, he appeared in the original production of Tennessee Williams’ “Orpheus Descending.”

After “Picnic,” he landed the male lead opposite Joan Crawford in the melodrama “Autumn Leaves” in 1956.

Robertson’s roles in the 1950s and ’60s in films such as “The Naked and the Dead,” “The Girl Most Likely,” “Gidget,” “All in a Night’s Work” and “Underworld U.S.A.” were largely undistinguished. He did professional work in “The Big Show,” “The Interns” and “My Six Loves,” but none of those pics ignited either.

Much of his best and most challenging early work came in television, including the lead in “Days of Wine and Roses” (a role he lost to Jack Lemmon in the film version), “The Game” in 1966 and “The Two Worlds of Charlie Gordon” (which became the film “Charly”).

He also made notable appearances on “Wagon Train,” “The U.S. Steel Hour,” “The Twilight Zone,” “The Untouchables” and “The Outer Limits.”

In 1966 he appeared as Shame, the cowardly villain, in several episodes of the “Batman” TV series.

His film career got a kickstart in 1962 when he was selected by President John F. Kennedy to play him in “PT 109,” based on the President’s exploits in WWII. Though the film was patriotic propaganda, the attention was just what Robertson had been looking for to separate him from the pack.

Slightly more visible roles followed including the action adventure “633 Squadron,” “Masquerade,” “Love Has Many Faces,” “Up From the Beach” and “The Honey Pot,” and he delivered a fine performance as a ruthless presidential candidate in “The Best Man,” based on Gore Vidal’s acerbic political drama.

With the film version of “Charly,” Robertson finally hit paydirt, winning the Oscar for his sensitive portrayal of a retarded man who temporarily has his IQ lifted through an experimental operation, only to descend to his normal state at the end. It was the perfect Academy Award vehicle, eliciting tears and respect.

In its wake, however, he often chose action vehicles like “The Devil’s Brigade,” “Too Late the Hero,” “Ace Eli and Rodger of the Skies,” “Shoot,” “Midway” and “The Great Northfield Minnesota Raid.”

In 1971 he tried his hand at directing “J.W. Coop,” a well-received tale of a would-be rodeo champion in which he starred in the title role. Later, in 1979, he directed “The Pilot,” a less successful drama.

He enjoyed strong roles in Robert Redford’s “Three Days of the Condor” and Brian De Palma’s “Obsession” and several TV projects including “Washington: Behind Closed Doors,” “My Father’s House,” “A Tree Grows in Brooklyn,” “The Man Without a Country” and “Two of a Kind.”

But his onscreen life was for a time overshadowed by the Begelman affair. In 1977, he received a W-2 tax statement for $10,000 from Columbia for money he had never received.

Inquiries led to excuses from Col, but Robertson stubbornly pursued the matter until the connection with Begelman was uncovered (Begelman had forged other checks totaling $40,000). The incident eventually forced Begelman out of Columbia. Soon after he resurfaced at MGM and then as head of his own production company. Begelman committed suicide in the mid-1990s.

Robertson, then a board member of SAG, told interviewers that his career lost its momentum as a result of incurring the displeasure of the old-boy network. He did get the occasional bite in Bob Fosse’s “Star 80,” “Brainstorm,” “Wind,” “Renaissance Man” and 1996’s “Escape From L.A.”

He more frequently worked in television, as a regular on Falcon Crest from 1983-84, and in TV movies such as “Ford: The Man and the Machine” (as Henry Ford) in 1987 and “Dazzle” in 1995. In 2003 he had a recurring role on NBC’s brief D.C. drama “The Lyon’s Den.”

On television he was also a spokesman for AT&T for some 10 years.

In 2002’s “Spider-Man,” Robertson played Peter Parker’s Uncle Ben, whose murder is a formative moment in the life of the young superhero. The actor also appeared in flashback scenes in the second and third entries in the film franchise.

Robertson served as a Screen Actors Guild board member for 30 years beginning in 1962 with a three-year stint in Hollywood. He then served as a national board member from the New York division from 1978 to 2005.

Robertson’s first wife was actress Cynthia Stone, the ex-wife of actor Jack Lemmon. In 1966 he married actress and heiress Dina Merrill. They had a child who died from cancer, and they divorced in 1989.

He is survived by his daughter by Stone, Stephanie.

Robertson died in Stony Brook, N.Y. His funeral is set for Friday in East Hampton. CLIFF ROBERTSON: 1923-2011