(Web Desk) - Juan Jumalon, known as DJ Johnny Walker, was shot inside his home-based studio, police said.
President Marcos Jr condemned the murder of the radio journalist "in the strongest terms".
Four journalists have been killed since Mr Marcos Jr took office in June of 2022, the National Union of Journalists in the Philippines said.
"The attack is even more condemnable since it happened at Jumalon's own home, which also served as the radio station," the union said.
Mr Jumalon was live-streaming on Facebook at around 05:30 local time when the suspect entered the recording booth and shot him.
According to local media, citing police sources, the suspect asked permission to enter Mr Jumalon's radio booth to announce "something important on air."
Police say they have already secured CCTV footage in the area.
Mr Jumalon's broadcasts are usually aired on 94.7 Gold Mega Calamba FM Facebook page, which has around 2,400 followers.
The DJ's wife took him to hospital immediately after the incident, but it is understood doctors pronounced him dead upon arrival.
Police said they were not aware of any previous threats against his life.
The president posted on X that he has instructed the police to conduct "a thorough investigation to swiftly bring the perpetrators to justice."
The Philippines is one of the most dangerous places in the world for journalists, says US-based Freedom House.