Almario Villegas, a former marine, was killed as police rescued Gina Ramos, the complainant in the case, along with two court clerks and a lawyer, who had been seized on Tuesday.
Ramos had filed an eviction notice against Villegas claiming ownership of a condominium in the capital.
Villegas, who said he had a grenade, fired shots in the air as he and Delia de la Cruz, his girlfriend, took the hostages to another room in the building.
De La Cruz was reportedly unharmed when police entered the Halls of Justice.
Ramos had demanded a ransom of $62,000 from Ramos's family to spare the lives of the hostages.
After leaving military service, Villegas did odd-jobs including working as a movie stuntman.
An investigation would be conducted to determine how the suspects managed to smuggle weapons into the courtroom, Sigfrido Tinga, the mayor of Taguig district southeast of
The authorities had evacuated an elementary school nearby as a precaution.