Footage from the scene shows the elderly woman walking the streets of central Brooklyn during daylight hours, with the suspect walking in the other direction.
He appears to be about to walk past her, but turns to face her before punching her in the face and casually walking away.
The 6:30pm assault took place just three blocks from the district police station.
It is unclear what motive lay behind the attack, which left the victim with a broken jaw and severe contusions to the left side of her face, which hit the ground as she fell to the floor.
Detectives from New York’s 71st district have since arrested a 27-year-old suspect Jaquan Rasheed Whittle, who is on probation.
Officers have confirmed he has been charged with violent assault.
NYPD Chief of Detectives Dermot F Shea thanked the people of New York and the “worldwide social media community” for sharing details of the suspect – saying that the tips garnered from the spread of the video led to Mr Whittle’s arrest.
Describing the assault as a “heinous, unprovoked attack” he added the 71-year-old victim was “getting the care and advocacy needed”.
According to NBC New York, the woman came round and walked into a shop, telling staff she could not remember what had happened but thought she had fallen.
Anabelle Beckford told the broadcaster: "When she first came in I was asking her, where were you - she didn’t even know where she was. I said, where did you fall. She said 'I don’t know, somewhere round here’."
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