He was one of the founding fathers of the Franco-Belgian comics movement, through his collaborations with Hergé and the graphic novel series that made him famous, Blake and Mortimer.

Financial good fortune did not follow, since the Great Depression hit the Brussels artistic community very hard.

After a career as extra and baritone singer in opera productions between 1919 and 1940 in Brussels and Lille, punctuated by small drawing commissions, Jacobs turned permanently to illustration, drawing commercial illustrations and collaborating in the children's weekly comic magazine Bravo until 1946, after he was introduced there by Jacques Laudy.

Jacobs subsequently published his first comic strip in Bravo, Le Rayon U (The U Ray), largely in the same Flash Gordon style.

As a direct result, he assisted Hergé in coloring the black and white strips of The Shooting Star from Le Soir in preparation for book publication in 1942, and from 1944 on he helped him in the recasting of his earlier albums Tintin in the Congo, Tintin in America, King Ottokar's Sceptre and The Blue Lotus for color book publication.

He then wrote the scenario for the second episode of Les Trois Formules du Professeur Sato, but the artwork remained unfinished at the time of his death.

The cemetery sphinx has a "collar" beard, and his face looks a lot like Philip Mortimer, the protagonist of most of the Jacobs albums.