Rivera was born in Penuelas, Puerto Rico, where his father and four uncles were Episcopal Priests. In 1944, he graduated from the Church Divinity School of the Pacific in Berkeley, California, and was ordained to the priesthood. From 1943 to 1944 he was vicar of Grace Church in Martinez, California, and from 1945 to 1968, he was rector of St. Paul's Episcopal Church, Visalia, California. He also held diocesan offices in the Diocese of San Joaquin.
In 1968, Rivera was elected third bishop of the Diocese of San Joaquin. He served until his retirement in January 1989, shortly after reaching the mandatory retirement age of 72. He was succeeded by bishop coadjutor John-David Schofield, who had been elected in the fall of 1988.
By the end of Rivera's episcopacy, the Diocese of San Joaquin was one of only six in the Episcopal Church that had not ordained any women to the priesthood. Rivera opposed the ordination of women and sexually active homosexuals during his episcopacy, describing his diocese as "not willing to do away with biblical teachings and the beliefs of the church." When his daughter Nedi was ordained to the Episcopalian priesthood in 1976, Rivera did not attend her ordination Service.
Rivera's wife, Barbara, died in April 2005, and he died eight months later on December 23 in Orinda, California.
