Video shows the moment a man wearing a black "I (heart) NY" sweatshirt and a backpack hit the 67-year-old "Ghostbusters" star and knocked him to the ground.
It happened Thursday at 7:24 a.m. on West 70th Street near Central Park West.
Friday afternoon police released a clearer image of the suspect.
The attack happened just a few blocks from the apartment building where Moranis' character, Louis Tully, lived in the movie.
The attacker continued walking north after throwing the punch.
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Moranis hurt his head, back and hip in the attack but was able to take himself to the hospital, and later, to the police station to report the incident.
Moranis' representative Troy Bailey said in a written statement Friday: "Rick Moranis was assaulted on the Upper West Side yesterday. He is fine but grateful for everyone's thoughts and well wishes."
Moranis shot to fame in the 1980s as a star of the sketch comedy series "Second City Television," before landing roles in blockbuster movies like "Ghostbusters" and "Honey I Shrunk the Kids."
He put acting aside in the late 1990s to focus on raising his kids but has made occasional appearances since.
Anyone with information in regard to this incident is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).
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Fellow actor Chris Evans, who portrays Captain America in the Marvel movie franchise, reacted to the attack on Twitter.
Information from the Associated Press was used in this story.
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