He was born in Davao City, Davao, Philippine Islands, and was married to Mercedes Cacho. He was the father of former Davao City mayor Sara Duterte, vice presidential daughter Inday Sara Duterte-Carpio, and former Davao 3rd District congressman Paolo "Pulong" Duterte.
A veteran of politics in Davao City, Alvarez first entered politics in 1965, when he was elected vice mayor of the city. His two-term mayoral tenure was marked by a campaign against Muslim rebels in the area, and an aggressive economic development program. He also supported the presidency of Ferdinand Marcos.
During Martial Law, Alvarez was elected representative of the 3rd District of Davao in 1978. He was reelected in 1980 and 1984. He was an integral part of Marcos's machinery and an ally of the late president.
When Marcos was overthrown in the People Power Revolution in 1986, Alvarez switched sides and joined President Corazon Aquino's government. He was subsequently appointed Secretary of National Defense.
In 1987, he was appointed as the Administrator of the Philippine Coconut Authority. He served until 1990.