Kerik will be under house arrest until Oct. 15, the New York Daily News reported. He was sentenced to four years in prison in 2010 for wire fraud, tax evasion and other crimes but was given early release for good behavior.
A crowd of reporters, photographers and camera crews waited outside Kerik's house in Franklin Lakes, N.J., but he went inside without making a comment. He could be seen hugging family members.
Al Manzo, owner of The Brownstone, a restaurant in nearby Paterson, N.J., said he was planning a welcome home feast for Kerik.
"Bernie's looking for some of the good food he hasn't been able to get for the last three years," Manzo told the News. "I'm his friend -- I'm there for him."
Kerik served as commissioner of the New York Police Department from August 2000 to Dec. 31, 2001, the end of Rudy Giuliani's term as mayor. He was at the World Trade Center on Sept. 21, 2001, when the second plane hit, showering him with debris.
In 2003, President George W. Bush named him Iraq's interim interior minister, effectively head of all national police forces, a position he held for a few months. Critics said Kerik spent most of his time on night-time operations, sleeping much of the day and giving the work of reorganizing Iraqi police short shrift.
Kerik's downfall began in December 2004 when Bush nominated him as secretary of homeland security. Kerik withdrew his name days later, saying he had hired an undocumented immigrant as a nanny.
Additional scrutiny from the news media turned up more damaging stories about Kerik, and a federal investigation began within months.