Henri Ghion, later known as Géri, made his debut at the age of sixteen, working as an apprentice of Raymond Reding. His first professional work were advertising illustrations. In 1953, he joined Studio Hergé as a colorist and artist of backgrounds. Then, Géri started making illustrations and short comics for Tintin. He created the kangaroo 'Pif' in the magazine Junior in 1962. The series was later renamed to 'Baf' and continued in Tintin. In 1966, he replaced 'Baf' by the absurd 'Skblllz' series.
In addition, he drew the 'Picratt' series in Pilote, scripted by Jacques Acar. In 1969, he started his most famous series, 'Mr Magellan', with texts by by Jean Van Hamme and later André-Paul Dûchateau, again in Tintin. In 1980, he illustrated 'Lady Black' in Tintin. He left the comics field due to a paralysis of his hand although in later years, he did produce an occasional painting.