 Fernández served in the New Mexico House of Representatives in 1935.He was the chief tax attorney for the New Mexico Tax Commission in 1935 and 1936 and the first assistant attorney general in 1937–1941.He was a member of the first New Mexico Public Service Commission in 1941 and 1942 and was elected as a Democrat to the 78th and to the six succeeding Congresses and served from January 3, 1943, until his death.