A police spokesperson told reporters that Alexander hit the cyclist Tuesday while he was driving along Wilshire Boulevard, in an area known as "Mid-City." Alexander stopped and waited for the police to arrive at the scene.
The 14-year old was not seriously injured and is reportedly in stable condition after being taken to hospital for examination.
Jason Alexander's publicist, Ron Hoffman, said the actor did the right thing by waiting for the police and paramedics to arrive. He has acknowledged responsibility for the accident.
Jason Alexander played the character of George Costanza, Seinfeld's neurotic friend, in the hit television series "Seinfeld."