In 1960, Montoya was assigned as resident engineer at the Long Beach Naval Shipyard. Montoya later served two tours in Vietnam, supervising Seabee construction of the first base camp in Da Nang and later of the Marine base at Chu Lai.[3]
In 1974, Montoya became director of the Navy Environmental Quality Division in Washington, D.C. In 1981, he became commanding officer of the Navy Public Works Center in San Diego, California. In 1984, Montoya assumed leadership of the Western Division Engineering Command in San Bruno, California.[3] His promotion to commodore was approved by the United States Senate on 16 October 1985.[5]
In 1986, Montoya was appointed director of the Shore Activities Division under the Deputy Chief of Naval Operations for Logistics in Washington, D.C. Approved for promotion to rear admiral on 15 May 1987, he then became commanding officer of Naval Facilities Engineering Command and chief of the Civil Engineer Corps. Montoya retired from active duty in November 1989.[1][6]
In November 1994, President Bill Clinton appointed Montoya to the Board of Visitors of the U.S. Naval Academy. He served as chairman of the board for two years.[3][8]
On February 8, 1995, President Clinton nominated Montoya to be a Defense Base Realignment and Closure Commissioner.[1][9][10] In September 2006, he was appointed to the Space Operations Committee of the NASA Advisory Council.[11]
Montoya was diagnosed with cancer in 2013.[2] After his death in December 2015, he was interred with full military honors at Coachella Valley Cemetery on January 6, 2016.[4]