Gumbay worked his way through the bureaucracy where he served for different school boards of his province.
When the Second World War erupted, Gumbay Piang, along with fellow Moro leaders such as Salipada Pendatun, organized the famed resistance group named the Moro-Bolo Battalion during the Japanese occupation of the Philippines to fight the Japanese.
[9][10] He was forced to retire from the resistance as a prisoner of war as he suffered chronic asthma attacks.
In 1946, he ran for Congress in the First Republic of the Philippines and won, representing the lone district of Cotabato.
In 1949, he succumbed to death in Manila due to asthma, marking the quiet exit of the Piangs from national politics.