Xavier Castellanos was born and raised in Geneva, Switzerland. He started painting at the age of four, later attending private painting workshops. He and his family moved to Mexico City, where he had his first solo show at the age of fifteen. After a series of very successful exhibits, he won public acclaim and admission into the Mexico City art circle. His works are held in numerous private and corporate collections. His talent has received recognition from many of the masters of Mexican art, including José Luis Cuevas and Raul Anguiano.

Xavier moved to New York City in 1991 to study Fine Art Painting at The Art Students' League, where he spent four years. His credits since 1988 include more than 50 solo exhibits and more than 70 group shows in the United States, Mexico, and Europe. He now divides his time painting between Mexico and San Francisco. While growing up in Geneva, he visited many European cities and their museums, a number of which he has revisited in the last 15 years. He has also traveled to Egypt, Morocco, Turkey, Japan, Thailand, Cambodia, and Singapore.

In 1995 Xavier won the competition "Art of the XXth Century" organized by the Louis O. Palmer Gallery at Muskingum College in New Concord, Ohio. He was awarded a prestigious grant by the National Fund for Culture and the Arts of Mexico in 1994.

He worked as a curator and coordinator for the 1992 exhibit "Passion for Frida" at the Mexican Museum of San Francisco; two of his paintings were included in this exhibit. He also presented a lecture entitled "Frida Kahlo and Mexican Art" at the UC Berkeley International House.

One of Xavier's paintings was reproduced on French telephone cards by Schlumberger to commemorate the issuance of their 100 millionth card in 1991. The same year he was commissioned to do the set, poster, and program design for the play "13 Rue de l'Amour" at the South Street Theater in New York City. His works have been selected for juried exhibits at the Davis Art Center (1996) and the Gallery House in Palo Alto (1995).