The former Saturday Night Live regular was travelling in the passenger seat of a friend's car in June (11) when another vehicle smashed into them in Sag Harbor, New York.
Hammond suffered fractured ribs and an injured back in the collision, which has caused him to axe some stand-up shows, as well as the final performance of his Broadway show Tru, where he was starring as Truman Capote.
On Monday (29Aug11), the actor's attorney filed a negligence suit in Manhattan.
The actor's lawyer, Melanie Little, tells New York Post gossip column Page Six, ""It affects his ability to perform. He's in pain and had to cancel many performances. He can't fly and he can't stand up.""
Hammond is seeking unspecified compensation from both his pal and the driver of the other vehicle.