The former star of 30 Rock's limousine van was hit by a truck early on June 7 on the New Jersey Turnpike. He suffered a broken leg and broken ribs in the crash.
Morgan's friend James McNair was killed and the actor and two other men were seriously injured.
His spokesman said that the actor is showing signs of improvement but has a long road to full recovery.
Lewis Kay did not identify the rehab facility where Morgan is staying, saying only that it is in New Jersey.