Fierro de Bright gave up her studies at UCLA to become an organizer, and her style was described by veteran longshoremen's leader Bert Corona as "gutsy, flamboyant, and tough".

In 1939 El Congreso leaders asked Fierro de Bright to help them to establish a branch in Los Angeles which represented a major effort by the Mexican American generation of the time, to form a working class movement that was aimed at securing basic rights for all Mexican and Spanish speaking people in the United States.

Her father Plumo Fierro, had been an officer in “Pancho” Villa's revolutionary army, but it was her mother's passion for activism and commitment to helping others that most strongly influenced her life.

Because Josefina's mother's family were followers of the radical Mexican anarchist Ricardo Flores Magón, she had been taught to speak against injustice, to fight for what was right and to treat everyone with “dignity and respect”.

[4] After high school graduation, Josefina Fierro decided to move to Los Angeles to live with an aunt; there she met and fell in love with Hollywood actor John Bright.

[6] Fierro de Bright, with Luisa Moreno, actively worked on issues that targeted the needs of lower-income and non-bilingual Mexicans to help them receive basic civil rights in the United States.

In 1942, during the “Sleepy Lagoon” trial, after receiving complaints of cruel punishment from parents of the boys held in custody, Fierro de Bright organized a committee for the defendants.