De Castelbajac has two fashion lines. He is also an actor, an artist, and owner of an Armagnac brand.[4]
De Castelbajac worked for several years in the menswear unit of his father's fashion label, and served as creative director of his Castelbajac Lignée collection.[3][5]
In 2007, he launched a line of fitted cotton t-shirts called Panda Kunst. The shirts tend to have politically based slogans.[1][2]
Later, he created another fashion label called Le Void, which refers to The Book of Five Rings by samurai Miyamoto Musashi.[3] The label consists of knit wear and t-shirts with plays on words written on them.[6]
He also collaborates with Tyler Alexandra Ellis to produce a bag line for her label, Tyler Alexandra. The line includes a bag with a beret top produced in France's oldest beret factory.[7][8]
De Castelbajac has also created t-shirts for OVS as part of an AIDS awareness campaign.[9][10]
De Castelbajac has appeared in plays, movies, and art films.[2] He lived in Los Angeles, California from age 19 to 25.[11] While he was there, he attended university and acted in two television pilots of Him and Us, directed by Charles Shyer.[12][13] He was in a Nespresso commercial with George Clooney, and was in a 2005 remake of Caligula.[1][2][14] He has appeared in art films by Marianne Maric and Mike Kelley.[15][16] In 2014, he acted in a film called The Permission, filming in Afghanistan and Scotland, and appeared in adidas commercials for the re-release of their Stan Smith style.[6][17]
Armagnac is an emblematic product of de Castelbajac's region of France. He created his Armagnac 700 in 2013, after researching and working with an oenologist for several years.[3][18] He designed the bottle himself, wrapping it in a felt ring made by the last beret producer in that region of France.[3] He produced a special collection for Colette, and the drink is also sold at Le Bon Marché, Harry's New York Bar, Hôtel Meurice, and Chateau Marmont.[19]
De Castelbajac has shown artwork in two solo exhibits. The first was an exhibit in Paris, France called The Anatomy of 1, a collection of drawings, collages, photos, and installations inspired by media violence.[1][13] His second exhibition was called The Blood, the Bow & Arrows of Desire.[20]
In 2010, he helped create a Bûche de Noel for Pierre Hermé.[21]