Admiral Rivero came to the Academy from Puerto Rico and after graduation and sea duty, attended MIT, receiving an MS in electrical engineering. During World War II he served in the cruisers USS San Juan (CL-54) and Pittsburgh (CA-72)

he participated in the landings at Guadalcanal-Tulagi, a raid on the Gilberts, the Battle of the Santa Cruz Islands, the South and Central Pacific Campaigns, the Solomon Islands Campaign, the capture of the Gilbert Islands, and the actions at Kwajalein, Iwo Jima, and Okinawa. In 1948 he was on the staff of Commander, Joint Task Force Seven, during atomic weapons tests in Eniwetok. During the Cuban Crisis in 1962-63 he was in command of Amphibious Force Atlantic. In 1964 he became VCNO under Admiral David L. McDonald, and later was CinC, Allied Forces, Southern Europe. Following his retirement in 1972, he was named as the U.S. Ambassador to Spain, earning him the sobriquet of the "Ambassador with the Seven League Boots."