The film follows notorious musician Serge Gainsbourg's exploits from his upbringing in Nazi occupied France through his rise to fame and love affairs with Juliette Gréco, Brigitte Bardot and Jane Birkin to his later experimentation with reggae in Jamaica.

The site's consensus reads, "It might be thinly written and messily made, but Gainsbourg: A Heroic Life is also appropriately glamorous and intense -- and powerfully led by a gripping performance from Erik Elmosnino.".

[7] Kenneth Turan of The Los Angeles Times enjoyed the film: Unconventional, imaginative, nothing if not audacious, Gainsbourg: A Heroic Life is a portrait of creativity from the inside, a serious yet playful attempt to find an artistic way to tell an emotional truth... the songwriter's life is heroic because he lived deeply in his own imagination and did continual battle with the personal demons who shared that space with him... Screenwriter Sfar's final word on his difficult, fascinating man is "I prefer his lies to his truth," his dreams to his reality.

Scott of The New York Times gave it a mixed review: [M]uch of the best and worst of Gainsbourg— the chat show provocateur and the charismatic performer — can be found on Internet video sites, which makes Gainsbourg: A Heroic Life feel a bit superfluous.

The puppets and the music make Gainsbourg: A Heroic Life engaging, but it is also visually hectic and lacks either the dramatic intensity or the arresting insight that might have lifted it out of the pedestrian realm of the admiring biopic.