His father, Juan Vincent Apablasa Sr., was of Chilean descent and his mother, Delia Diana Pablos, was a Mexican-born aristocrat.

[2][3][4] After attending Roman Catholic schools, St. John's Military Academy (Los Angeles), and Villanova Preparatory (Ojai, California), he earned a Bachelor of Arts in economics degree and Latin American affairs[citation needed] from Stanford University, where he was in the Navy ROTC,[5] did senior honors work in Latin American economic history, and was a member of Chi Psi fraternity.

Due to Gavin's fluency in both Spanish and Portuguese, he was assigned as flag lieutenant to Admiral Milton E. Miles until he completed his four-year tour of duty in 1955.

[6] In a 1960 interview, Gavin disputed rumors that he was born into wealth by revealing that he attended a preparatory school and Stanford University on scholarships.

[7] Following his naval service, Gavin offered himself as a technical adviser to family friend and film producer Bryan Foy, who was making a movie about the Princeton.

Gavin was meant to star in The Female Animal (1958) but was too busy on other projects and was replaced by George Nader.

Following the success of Imitation of Life, Gavin was often cast as the handsome opposite to leading ladies but as characters who were permitted little action.

[18] He co-starred against Doris Day in the thriller Midnight Lace, Sophia Loren in the comedic A Breath of Scandal (both 1960),[15] Susan Hayward in the melodrama Back Street and with Sandra Dee in Romanoff and Juliet and Tammy Tell Me True (all 1961).

"[19]Gavin disliked comparisons to Rock Hudson and in a 1960 interview said he considered quitting acting to take up law.

His next role was that of Mary Tyler Moore's character's stuffy boyfriend in Universal's 1920s-era musical Thoroughly Modern Millie (1967).

[23] He was cast in the lead in OSS 117 – Double Agent (1968), then titled No Roses for Robert, replacing Frederick Stafford who was filming Alfred Hitchcock's Topaz.

[citation needed] In 1973, Gavin replaced Ken Howard in the Broadway musical Seesaw opposite Michele Lee.

[32] Gavin said he first turned down the musical because of his unhappiness with the quality of the book but reconsidered when Michael Bennett asked him to join the cast.

[15] In 1973, Gavin played Akhenaten in the television movie Nefertiti y Aquenatos alongside Geraldine Chaplin and Salah Zulfikar.

He met with opposition political parties while being a key defender of the President's anti-communist policies within Central America, which he received attention and scrunity for.

[37] In June 1986 following his work as ambassador to Mexico, Gavin became vice-president of Atlantic Richfield in federal and international relations.

[38][39] Gavin was president of Gamma Holdings, a global capital and consulting company which he helped found in 1968.

He served on the boards of Causeway Capital, the Hotchkis & Wiley Funds, the TCW Strategic Income Fund, Securitas Security Services USA, Inc., DII Industries, LLC, Claxson Interactive Group Inc., Anvita, Inc., the Latin America Strategy Board at HM Capital Partners LLC, Apex Mortgage Capital Inc., Krause's Furniture, Inc., Atlantic Richfield Co., International Wire Holdings Company and International Wire Group Holdings, Inc.[citation needed] Gavin served as senior counselor to Hicks Trans American Partners (a division of Hicks Holdings) and managing director and partner of Hicks, Muse, Tate & Furst (Latin America) from 1994 to 2001.

[citation needed] Gavin served on various pro bono boards, including UCLA's Anderson Graduate School of Management, Don Bosco Institute, the FEDCO Charitable Fund, the Hoover Institution, Loyola-Marymount University, the National Parks Foundation, Southwest Museum, the University of the Americas and Villanova Preparatory School.

[45] Gavin died of complications from pneumonia after a long battle with leukemia on February 9, 2018, at his home in Beverly Hills.