At the age of 18, the young Toulousan was admitted to the Cours Jean Périmony in Paris. In 1982, he entered the École nationale supérieure des arts et techniques du théâtre. Before entering the Comédie-Française, Christian Gonon was noticed for his interpretations of Count de Guiche in Cyrano de Bergerac by Rostand directed by Jérôme Savary in 1983, of d'Artagnan in The Three Musketeers by Jean-Louis Martin-Barbaz (Jean Marais prize for best actor in 1991) and of Lacroix in The Death of Danton by Büchner directed by Philippe Lanton in 1998. After playing Eilif in Mère Courage et ses enfants by Brecht, directed by Jorge Lavelli, Christian Gonon joined the Comédie-Française on July 1, 1998, becoming a member on January 1, 2009. He distinguished himself in many roles, including Maxime in Cinna by Corneille directed by Simon Eine, Bassanio in The Merchant of Venice directed by Andrei Serban, the Man and the Fox in Fables by La Fontaine directed by Robert Wilson, Cassius in Tête d'or by Paul Claudel directed by Anne Delbée, De Ciz in Partage de midi by the same author directed by Yves Beaunesne, Gremio in The Taming of the Shrew by Shakespeare directed by Oskaras Koršunovas. He played in Ubu roi by Jarry under the direction of Jean-Pierre Vincent and in Un fil à la patte by Feydeau under Jérôme Deschamps. Denis Podalydès directed him twice: in Cyrano de Bergerac by Rostand and in his version of Lucrèce Borgia by Victor Hugo. More recently, Christian Gonon has performed in shows by Éric Ruf (as Tybalt in Shakespeare's Romeo and Juliet), Katharina Thalbach (Brecht's The Resistible Ascension of Arturo Ui), Lars Norén (who created his latest play, Poussière, at the Salle Richelieu) and Clément Hervieu-Léger (Wedekind's Spring Awakening).

In the cinema, he acted, among others, under the direction of Sébastien Gabriel in Et si je parle (2005) and Guillaume Georget in Les hommes sont des rêves (2011), as well as in various short films, including Memento by Jean-Max Peteau (1992), which won the Avoriaz Grand Prix and the Clermont-Ferrand Audience Award. He is the French voice of Colin Firth and Christoph Waltz in many films.

As a director, Christian Gonon presented Fabrice Melquiot's play for young audiences Bouli Miro at the Studio-Théâtre in 2004, in which he also played the title role. In 2016, he adapted and performed, as part of the Singulis, Samuel Beckett's Compagnie, a first stage version of which was performed at the Comédie-Française by Pierre Dux in 1984.

This season, he reprises his role as Ned Land and the manipulation of puppets in Twenty Thousand Leagues Under the Sea by Jules Verne, directed by Christian Hecq and Valérie Lesort at the Théâtre du Vieux-Colombier, as well as that of the Count in Il faut qu'une porte soit ouverte ou fermée by Musset, directed by Laurent Delvert at the Studio-Théâtre. He also proposes a Grenier des acteurs on January 8, a reading of excerpts from La pensée, la poésie et le politique - dialogue with Jack Ralite by Karelle Ménine, Salle Richelieu at La Coupole.