George Perrett suffered a fatal cardiac arrest early Saturday as he received treatment in hospital for a gunshot wound to the thigh, said Superintendent Jomar Yap, the deputy chief of police of Sarangani province.
Perrett, the mayor of the coastal town of Maitum on the southern tip of the Philippine islands, was shot by unknown gunmen as he drove home with his wife and an aide late Friday, Yap added. His companions were unhurt.
Police said no suspects had been arrested and the authorities did not know if the attack was politically motivated.
Maitum has a blood-spattered recent political history, losing two other sitting mayors in as-yet-unsolved gun attacks.
Perrett was a political ally of global boxing icon and Philippine legislator Manny Pacquiao, who urged the police to bring the unknown suspects to justice.
"We are saddened by this very unfortunate incident. I urge our law enforces to expedite the investigation of the case and do everything to identify and arrest those responsible," Pacquiao told reporters.
Then mayor George Yabes was shot dead in Maitum in 2006 and Felix Reganit, who succeeded him, was gunned down in the Philippine capital Manila later that year.
Former Maitum mayor Exuperio Gaabucayan was also ambushed and killed there in 1990, police said.