
While still a teenager, he began writing in Tagalog for the newspaper Watawat (Flag). He would later write a column for the Tagalog publication Pagkakaisa (Unity) and become editor of Mabuhay (Long Live).
His writings gained the attention of Tagalog literati and some of his stories and poems were included in anthologies, such as Clodualdo del Mundo's Parolang Ginto and Alejandro Abadilla's Talaang Bughaw.
In 1922, at the age of 19, Hernandez became a member of the literary society Aklatang Bayan which included noted Tagalog writers Lope K. Santos and Jose Corazon de Jesus.
In 1932, he married the Filipino actress Atang de la Rama. Both of them would later be recognized as National Artists: Hernandez for Literature, de la Rama for Theater, Dance and Music.