Tovar was discovered by documentary filmmaker Robert Flaherty in Mexico City. Tovar had performed in a dance class and was invited, along with other girls, to do a screen test as part of a competition. Tovar won first place. The prize was a 6-month probation period, followed by a 7-year contract at $150/week, to Fox Studios. The studio had realized they could make money by simultaneously shooting Spanish-language movies of English language studio productions, so had been casting for Spanish stars. She moved to Hollywood in November 1928 with her maternal grandmother, Lucy Sullivan.