Clint Hill, the Secret Service agent who leaped onto President John F. Kennedy’s limousine as it came under fire in Dallas and prevented a scrambling Jacqueline Kennedy from falling to the ground, died on Friday at his home in Belvedere, Calif. Mr. Hill, hailed for his bravery but long tormented by his inability to save the president’s life, was 93.

His death was announced on Monday by Jennifer Robinson, his publicist.

It is a signature image of the Kennedy assassination, reproduced in an Associated Press photograph and the amateur motion picture footage known as the Zapruder film: A figure in a business suit grasps the trunk of the presidential limousine as Mrs. Kennedy, in her pink outfit and matching pillbox hat, climbs onto the rear of the auto.

Mr. Hill, the man in the suit, who was assigned to protect Mrs. Kennedy, pushed her back into her seat, alongside her mortally wounded husband.

“I think Special Agent Clinton Hill saved her life,” David F. Powers, an aide to Mr. Kennedy who was riding in the backup Secret Service car, later told the Warren Commission investigating the president’s assassination.

Mr. Powers said that Mrs. Kennedy “probably would have fallen off the rear end of the car and would have been right in the path of the other cars proceeding in the motorcade.’’

Thirteen days after the assassination, in a ceremony attended by Mrs. Kennedy, Mr. Hill received the highest award bestowed by the Treasury Department — the agency that oversaw the Secret Service at the time — for his “extraordinary courage and heroic effort in the face of maximum danger.”