His parents were José de la Luz Hernández and Amadita Rodríguez. He has a brother, Héctor Hernández. He was left fatherless, and his mother took him to Mexico City in 1956. He studied accounting, although his vocation was acting. He married Edith Sánchez, with whom he became the father of Aarón and Edith.
He debuted as a theater actor in the 1950s, in the play Las manos sucias, by Jean-Paul Sartre, with the participation of Tere Velázquez, Carlos Bracho and Sergio Barrios. Once settled in Mexico City, he entered the Instituto Cinematográfico, Teatral y Radio-Televisión, of the Asociación Nacional de Actores (ANDA), directed by Andrés Soler. In 1958, he participated in another festival, with the ICT's Moncell group, where he starred in El gesticulador, a play by Rodolfo Usigli.
He made his film debut in 1965 with Viento negro, as a supporting actor. After participating in the play Moby Dick, he was called by Ernesto Alonso to work in television. He made his television debut in the soap opera La mentira (1965), with Julissa, Enrique Lizalde and Fanny Cano.
He worked in the theatrical company of the Mexican Social Security Institute.
Aarón Hernán served as Secretary of Internal and External Affairs and Treasury of the National Actors Association (ANDA) on several occasions and served as General Secretary from 1998 to 2002.
In his last year of life, his children wanted to declare him legally incompetent to administer his assets, so he had to defend himself legally and moved to La Casa del Actor, ANDA's retirement home. There he had a fall that caused him to fracture his femur. Complications following surgery caused a lethal myocardial infarction.
