Born Blanca Rosa López Rodríguez to a prominent Guatemalan family, Rodríguez moved to the United States in her early 20s and changed her name to Luisa Moreno. When the Great Depression hit in the 1930s, Moreno joined the Communist Party and—later—the Congress of Industrial Organizations (CIO) in 1934.

Serving as a full-time advocate for immigrant laborers everywhere, Moreno traveled across several states, drawing attention to the abominable working conditions in sweatshops, canneries and agricultural fields. In 1938, Moreno established the Congreso de Pueblos que Hablan Español (National Congress of Spanish-Speaking Peoples). In the 1950s, amid rising tension as a result of the “red scare”, Moreno left the U.S. for Mexico City, where she continued to organize workers in Mexico, Cuba and Guatemala.