Paul Jamin began his career drawing for scouting magazines. His first comic was 'La Belgique à travers les Ages', which appeared in Boy-Scout in 1930-31. He was one of Hergé's collaborators in the days of Le Petit Vingtième. Together with Hergé and a couple of other cartoonists, Jamin worked on the editorial pages of this children's supplement of Le XXe Siècle from 1930 to 1936. They signed their editorial work under the collective pseudonym of Oncle Jo. Between 1935 and 1944 he worked for numerous other magazines, signing his work mostly with Jam, Jamin or Alfred Gérard. In 1936, Jamin became the political caricaturist for Léon Degrelle's rightwing paper Le Pays Réel.
Cover for Le Petit Vingtième (19 October 1933)
During the War, Jamin drew for papers like Le Soir and Brüsseler Zeitung, that were both under German supervision. He launched Le Soir-Jeunesse together with Hergé and Jacques van Melkebeke, a supplement of Le Soir. He filled editorial pages under the pseudonym Monsieur Triplesec. He made various anti-semitic drawings before and during the War, which got him sentenced to death after the Liberation.
However, this wasn't executed, and Jamin was released from prison in 1952. He resumed his artistic activities by making caricatures for the satirical weekly Pan, using the pseudonym Alidor. He was also present in Spirou with nine stories for the mini-books section, as well as the continuing story 'Le Vol du Bourdon' starring the character Ernest Lecrac in 1962.