States citizen at the age of 23, and returned to Douglas in order to pursue a career in teaching. He was turned down for employment due to being a Mexican immigrant, and was discouraged enough to hop onto a freight train and pursue boxing professionally, earning fifty dollars per fight. Later, he decided to once again return to Douglas and work for the U.S. Department of State as a foreign service clerk in Agua Prieta, a border city in his native Sonora. He was convinced by a friend to quit his job with the State Department and instead pursue a career as a lawyer, and decided to attend the University of Arizona College of Law. In order to pay his way through law school, Castro became a Spanish professor at the University of Arizona due to a sudden opening, but this caused complications with his admittance to law school as the dean felt he would not be able to dedicate himself to his studies while also maintaining a job as an educator. Castro had developed a relationship with the university's president, who contacted the dean of the law school and subsequently convinced the dean to admit Castro. Castro earned his Juris Doctor degree and was admitted to the Arizona Bar in 1949. In 1959, he married his long-time girlfriend, Patricia Steiner, and they had two daughters. Law career, U.S. Ambassador to El Salvador, Bolivia After earning his law degree from the University of Arizona, Castro practiced law for two years in Tucson and subsequently served as a deputy county attorney for Pima County, Arizona. At the time, Mo Udall was the county attorney, and upon his retirement gathered all of the deputy county attorneys to inform them that he had handpicked his successor, Ed Larkin. Castro walked out of the meeting, angered by the dictatorial way that Udall had selected his successor despite county attorney being an elected position, and in 1954, Castro decided to run for the position himself. Castro won the election by 65 votes, becoming the first Mexican American to hold such a position in the state. He served in that capacity until 1958 when he became a Pima County Superior Court Judge. Castro earned a growing reputation during his time as a Superior Court Judge, and received a call from Roy Elson, an aide to U.S. Senator Carl Hayden who offered Castro a position as a