A Manhattan Citibank personal banker swiped more than $150,000 from an elderly man battling dementia and used some of the dough to treat himself to a Harley-Davidson motorcycle, authorities said Tuesday.

Juan Velez, 35, of Hoboken, NJ, had faced up to 15 years behind bars for his crime but ended up copping a plea deal that landed him a six-month jail term Tuesday on a grand larceny charge, prosecutors said.

Velez, who worked on the Lower East Side, admitted to stealing $166,000 from a 79-year-old client over a year, authorities said.

He used his victim’s money to pay off his credit-card bills and to splurge on the hog between April 2022 and April 2023, according to court documents.

Prosecutors said the victim visited the Citibank branch several times a week to speak with Velez after getting confused about what was going on with his money.

But Velez, who was actively stealing from the victim, blamed the elderly man’s frequent visits on his memory problems.

Velez’s scheme included setting up fake accounts disguising himself as the elderly man and using them to transfer money to himself, according to prosecutors.

The former banker was arrested in May, a month after his last transaction.

Manhattan District Attorney Alvin Bragg urged any elders who suspect they’re financial-fraud victims to reach out to his office’s Elder Abuse Unit.

“Today, Juan Velez is facing accountability for abusing his position as a personal banker to steal from a 79-year-old man suffering from dementia,” Bragg said in a statement.

“We are committed to protecting older New Yorkers from fraudsters who target their well-earned savings.”

As part of the plea deal, Velez will also have to serve five years probation after his six-month sentence — in addition to turning over the motorcycle and paying money to Citibank.

His attorney, Patrick Parrotta, did not respond immediately to a Post request for comment.

Velez will be sentenced Dec. 3.