He spent his childhood and adolescence in Barcelona, where he studied Architecture, and his brother David studied the Arts. In 1980 he founded the label Custo Line with his brother David which in 1996 became Custo Barcelona and today is a label of Blue Tower S.L., Barcelona. Initially focusing on printed tops and T-shirts inspired by the looks of Californian surfers, the label meanwhile has added a full range of women's clothing, a men's line, as well as shoes and accessories. Since 2008 licenses for fragrances and perfumes have been issued.
Specialty of the Catalan fashion label are complex and colorful graphical prints and intricate textile finishing which evolved over the years based on the architecture and design background of the Dalmau brothers. Over the years Custo Barcelona has been very successful with celebs in Hollywood, his fashion styles have even on show in several films. Custo Dalmau has appeared in many Spanish-language TV series and shows. The label is available globally in more than 40 countries through about 80 own shops and 3.000 fashion retailers and expands heavily in Northern America, Latin America and Asia. The label regularly takes part in Mercedes-Benz Fashion Show New York, but also shows in Miami, in Lima (Peru), several times in Berlin (Germany) and lately in Shanghai.
In his private life, Custo Dalmau is married to Eva Vollmer who is responsible for the label's kids line Custo Growing. The couple have a daughter together. Custo Dalmau is father to 3 daughters (one of which is not his biological daughter) and two sons in a patchwork family. He spends his time between the family home in Barcelona and the US which is the most important market for Custo Barcelona.