J. Crespo become French junior champion in 1943 then French senior champion in 1944 in a Perpignan team including Joseph Desclaux, Puig-Aubert and Frédéric Trescases against Avigon bayonnais of Jean Dauger with a score of 20–5.

Within the Roanne club, alongside René Duffort with whom he perfected the crossing pass, he won the French Championship twice in 1947 and 1948, then he joined U.S. Lyon-Villeurbanne for two other titles in 1951 and 1955, supplemented by two Coupe de France titles in 1953 and 1954.

He is one of the best scrum-half in the French Championship, capable of playing five-eight or centre with equal success, he also has 28 caps with the France national team, taking part in the titles of European Rugby League Championship in 1949, 1951 and 1952, participating at the 1951 French rugby league tour of Australia and New Zealand, and the World Cup final in 1954.

He earned 26 caps for France, between 1948 and 1954, taking part to the 1951 French rugby league tour of Australia and New Zealand and the 1954 World Cup.

During his active life, he worked as sales rep for home improvement articles.