Frédéric Jannin made his debut in the music magazine More, where he created the character 'Rockman' with text by Jean-Claude de la Royère. In 1977, he began his famous 'Germain et Nous' series in the Spirou supplement Le Tromone Illustré. Jannin initially worked with Thierry Culliford as his scenarist, but he eventually began writing the gags himself or cooperating with Yvan Delporte, Alain De Kuyssche or Serge Honorez.
Also for Spirou, Jannin began 'Arnest Ringard et Augraphie' (text by Yvan Delporte and André Franquin), as well as the gag strip 'Didi' (text by Alain De Kuyssche) and 'Les Collectioneurs' (text by Delporte). He teamed up with De La Royère again in 1984 to create 'Jimmy Laventure' at Dargaud. A year later, he started 'Nougat le Rat' in L'Argonaute with Serge Honorez.
In the early 1990s, he began an intense cooperation with the scenarist Stefan Liberski in both animation and comics. They developed the animation series 'Les Snuls', as well as some animation projects for Canal+. For the juvenile press, they created the comics series 'Les Aventures de Petit Jules et Pépé Jules'.