They say the suspect, identified as James Walton, allegedly struck banks in Greenwich Village, the Flatiron district, midtown and the Upper East Side and Upper West Side.
In each case, police say he passes a note to the teller and demands cash. To date, the suspect has gotten away with about $3,400, authorities said.
The first bank robbery occurred on March 6. The most recent one was on Monday.
Anyone with information about Walton or the robberies is asked to call the NYPD Crime Stoppers at 800 577-TIPS.