The deal, announced jointly on Tuesday by Walsh and Lifetime, will return to the air Walsh's weekly criminal roundup, which since 1988 has helped bring almost 1,200 fugitives to justice.
The series will return for its 25th season later this year.
"`America's Most Wanted' is a seminal program that provides a very valuable service to both viewers and law enforcement agencies," said Lifetime president Nancy Dubuc. "For more than two decades John Walsh has been leading the fight against crime and it's an honor to partner with him on bringing back this important show."
"We've often been called the court of last resort," Walsh said. "Now we are back in the game and ready to saddle up for another season to get justice for victims and put dangerous criminals behind bars."
In May, Fox announced it was axing "AMW," citing high production costs. At the time the network said it would present four quarterly specials in the coming season. The first of those specials will air in October, and Fox will follow it with the remaining three, Walsh said.
But Fox's final weekly "AMW" was telecast in June.
"We kept the hotline and website up, and we've caught four guys," Walsh said. "The viewers didn't give up on us."
Since then, Walsh had been in talks to find a new network. The deal with Lifetime was completed Tuesday afternoon, he said.
It was in 1981 that Walsh launched his crime-busting crusade in the aftermath of the abduction and murder of his 6-year-old son Adam. He became an outspoken advocate for tougher laws against sex offenders, more cooperation among law enforcement agencies, and citizen involvement in flushing out fugitives.
He was a former hotel executive with no TV experience, but his TV show premiered in April 1988 on the fledgling Fox network and, little more than a year later, it was the first-ever Fox program to rank first in viewership in its time slot. It remained a fixture on the network after that, and during the 2010-11 season, was seen by an audience averaging 5 million viewers.
In a happy coincidence, on Saturday, Walsh will get a special Emmy Award saluting his show. The Academy of Television Arts & Sciences will give Walsh its Governors Award at the Creative Arts Emmys ceremony in Los Angeles. The honor goes to a person or organization that makes a substantial impact or demonstrates an extraordinary use of television.