Some Pakistanis are happy to see the return of the ex-military ruler, hoping his leadership could help restore order to a country riddled with political division and plagued by extremist violence.
But he also made many enemies in the final years of his presidency, notably among the judges he allegedly detained.
The Pakistani Taliban vowed to send a death squad to hunt down the former president if he returned to the country, though Musharraf has said he has been living under threats of death since September 11, 2001, when he supported the American war on terror and fought against the Taliban.
The former general became president after a bloodless coup in 1999.
Musharraf's popularity began declining in 2007 after he suspended the nation's Supreme Court chief justice for "misuse of authority." The move resulted in protests and accusations that he was attempting to influence a court decision on whether he could seek another term in office.