Gaël Kamilindi was born in the Democratic Republic of Congo, and grew up in Switzerland. As a child, he was part of the Bus et Compagnie, a youth series on the Swiss Romand TSR television channel. Director Sandra Amodio suggested that he studied theater at the Geneva Conservatory where he was most notably taught by actress Anne-Marie Delbart. In 2008, he trained at the Paris Conservatoire national supérieur d’art dramatique, in classes taught by Dominique Valadié and Alain Françon.

Three years later, he upheld the role of Harold alongside Catherine Salviat in Colin Higgins’ Harold and Maude, directed by Jean Liermier in Geneva’s Théâtre de Carouge. The following year, Joël Dragutin cast him in Une Maison en Normandie, at the Cergy-Pontoise Théâtre 95.
In 2013, he interpreted Tonino alongside Dominique Blanc in Carlo Goldoni’s La Locandiera directed by Marc Paquien at the Théâtre de l’Atelier. In 2014, Patrice Chéreau offered him a role in William Shakespeare’s As You Like It. The play was cancelled following the director’s death. Gaël Kamilindi interpreted Village, in Jean Genet’s Les Nègres directed by Robert Wilson at the Odéon-Théâtre de l’Europe.
Between 2014 and 2016, he appeared alone on stage to perform the text by Rodrigue Norman and Catherine Verlaguet Venavi ou pourquoi ma sœur ne va pas bien directed by Olivier Letellier. In 2015, Jean-Pierre Vincent directed him in Waiting for Godot (En attendant Godot), at the Marseille Théâtre du Gymnase. The same year, Krzystzof Warlikowski offered him the role of Hyppolyte 1 in Phèdres(s) after Wajdi Mouawad, Sarah Kane and John Maxwell Coetzee, staged at the Odéon-Théâtre de l’Europe and starring Isabelle Huppert in the title role.
In January 2017, he played in Le Dernier Testament, adapted by Mélanie Laurent and Charlotte Farcet from James Frey’s Last Testament of the Holy Bible, and directed by Mélanie Laurent at the Théâtre national de Chaillot.

On the 1st of February 2017, he joined the Comédie-Française as a pensionnaire and made his debut as Gennaro in Victor Hugo's Lucrezia Borgia by Denis Podalydès, who also offered him the role of Léandre in Scapin the Schemer (Les Fourberies de Scapin) by Molière.

For television, Gaël Kamilindi has filmed with Stéphane Kurc in J’adore ma vie, Benoît Cohen in Tiger Lily, and Raymond Vouillamoz in Déchaînées. On film, he was directed by Vasily Serikov in 22 minutes, Catherine Corsini in An Impossible Love (Un amour impossible) and Éléonore Pourriat in I am not an Easy Man (Je ne suis pas un homme facile).

During the 2018/2019 season, Gaël Kamilindi plays in Electra/Orestes after Euripides by Ivo van Hove. His Grenier des acteurs is dedicated to William Blake. He can also be seen in the reruns of Victor Hugo’s Lucrezia Borgia and Molière’s Scapin the Schemer (Les Fourberies de Scapin), both directed by Denis Podalydès.