Mayor Bill de Blasio Wednesday defended his decision to hire a general manager for the city's public housing system who left a past job over an affair with a subordinate.

Michael Kelly, who will replace Cecil House as general manager of the New York City Housing Authority, held the same job at Philadelphia's counterpart when he abruptly quit the post in 2012.

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"He made a mistake in Philly. There's no two ways about it. He owned up to it," de Blasio said.

Philadelphia's housing authority policy bars fraternizing among senior staff and subordinates.

An investigation by the U.S. Department of Housing and Urban Development found no evidence that the married Kelly misused federal dollars on the aide with whom he had the affair.

"Human beings make mistakes, but if they own up to it and if they don't do anything that harms the work, I think, you know, it's right to give someone another chance," the mayor said.

Kelly has been credited with turning around housing agencies in San Francisco, New Orleans and Washington, D.C.