Haenel made her film debut in 2002 at the age of 12, playing an autistic girl in the Christophe Ruggia film Les Diables.
She had been chosen for the lead role after accompanying her brother to the audition.
After Les Diables, Haenel took a five-year break from acting.
In 2007, she was persuaded by casting director Christel Baras (who had cast her in her film debut) to resume her film career, taking up the part of a synchronised swimmer in Céline Sciamma's debut feature Water Lilies.
Manohla Dargis of The New York Times highlighted Haenel's performance in an otherwise mixed review of the film, recognizing her as having "the makings of a real star".
For her role in the film, Haenel was nominated for the César Award for Most Promising Actress in 2008.
In 2012, she was nominated in the same category for House of Tolerance (2011), a period film directed by Bertrand Bonello, in which she played a prostitute at an upscale Parisian brothel at the turn of the twentieth century.
She also received the Lumières Award for Most Promising Actress along with her co-stars Céline Sallette and Alice Barnole.

Haenel played one of the two sisters in Katell Quillévéré's Suzanne (2013), for which she received the César Award for Best Supporting Actress.
In 2014, Haenel starred in the Thomas Cailley romantic comedy Love at First Fight as Madeleine, a graduate-school dropout and survivalist.
She won the César Award for Best Actress for her performance.
In the same year, Haenel co-starred with Catherine Deneuve in André Téchiné's crime drama In the Name of My Daughter, playing the daughter of a casino owner.
Writing for The Village Voice, Melissa Anderson compared her performance to that of Isabelle Adjani's in the 1970s and '80s, and declared her a worthy successor to Deneuve in French cinema.
For her roles in both films, Hanael received a Best Actress nomination at the 20th Lumières Awards.

In 2016 Haenel made her German language debut in the film The Bloom of Yesterday playing the French descendant of German Holocaust survivors.

In the 2017 Robin Campillo film BPM (Beats per Minute), Haenel portrayed Sophie, a headstrong HIV/AIDS activist of the Paris chapter of ACT UP.
She received a nomination for the César Award for Best Supporting Actress for her performance.

Haenel starred in the 2018 Pierre Salvadori crime comedy The Trouble with You, playing a widowed detective based on the French Riviera.
David Rooney of The Hollywood Reporter noted her performance as evoking the "classic screwball heroine", a departure from her usually more serious roles, and complimented her on the "grace and buoyancy" she brought to the character.
She was again nominated for the César Award for Best Actress.

In 2019, Haenel appeared in three films which played at the Cannes Film Festival: Quentin Dupieux's Deerskin, Aude Léa Rapin's Heroes Don't Die, and Céline Sciamma's Portrait of a Lady on Fire.
In Portrait of a Lady on Fire, Haenel portrayed Héloïse, a young aristocrat in 18th-century Brittany who is to be married off to a nobleman from Milan.
The New Yorker's Richard Brody took note of her chemistry with co-star Noémie Merlant and complimented the actresses for being "relentlessly graceful, endowed with physical aplomb, contemplative insight, and strong emotion".
A. O. Scott of The New York Times considered Haenel's performance worthy of an Oscar nomination for Best Actress, and Bilge Ebiri of Vulture described the climax of the film (which features Haenel) as "one of the finest pieces of acting and one of the most moving images I’ve seen in eons."
Haenel was nominated for the César Award for Best Actress for her performance, her seventh César nomination.
Haenel made her film debut in 2002 at the age of 12, playing an autistic girl in the Christophe Ruggia film Les Diables. She had been chosen for the lead role after accompanying her brother to the audition. After Les Diables, Haenel took a five-year break from acting. In 2007, she was persuaded by casting director Christel Baras (who had cast her in her film debut) to resume her film career, taking up the part of a synchronised swimmer in Céline Sciamma's debut feature Water Lilies. Manohla Dargis of The New York Times highlighted Haenel's performance in an otherwise mixed review of the film, recognizing her as having "the makings of a real star". For her role in the film, Haenel was nominated for the César Award for Most Promising Actress in 2008. In 2012, she was nominated in the same category for House of Tolerance (2011), a period film directed by Bertrand Bonello, in which she played a prostitute at an upscale Parisian brothel at the turn of the twentieth century. She also received the Lumières Award for Most Promising Actress along with her co-stars Céline Sallette and Alice Barnole.
Haenel played one of the two sisters in Katell Quillévéré's Suzanne (2013), for which she received the César Award for Best Supporting Actress. In 2014, Haenel starred in the Thomas Cailley romantic comedy Love at First Fight as Madeleine, a graduate-school dropout and survivalist. She won the César Award for Best Actress for her performance. In the same year, Haenel co-starred with Catherine Deneuve in André Téchiné's crime drama In the Name of My Daughter, playing the daughter of a casino owner. Writing for The Village Voice, Melissa Anderson compared her performance to that of Isabelle Adjani's in the 1970s and '80s, and declared her a worthy successor to Deneuve in French cinema. For her roles in both films, Hanael received a Best Actress nomination at the 20th Lumières Awards.
In 2016 Haenel made her German language debut in the film The Bloom of Yesterday playing the French descendant of German Holocaust survivors.
In the 2017 Robin Campillo film BPM (Beats per Minute), Haenel portrayed Sophie, a headstrong HIV/AIDS activist of the Paris chapter of ACT UP. She received a nomination for the César Award for Best Supporting Actress for her performance.
Haenel starred in the 2018 Pierre Salvadori crime comedy The Trouble with You, playing a widowed detective based on the French Riviera. David Rooney of The Hollywood Reporter noted her performance as evoking the "classic screwball heroine", a departure from her usually more serious roles, and complimented her on the "grace and buoyancy" she brought to the character. She was again nominated for the César Award for Best Actress.
In 2019, Haenel appeared in three films which played at the Cannes Film Festival: Quentin Dupieux's Deerskin, Aude Léa Rapin's Heroes Don't Die, and Céline Sciamma's Portrait of a Lady on Fire. In Portrait of a Lady on Fire, Haenel portrayed Héloïse, a young aristocrat in 18th-century Brittany who is to be married off to a nobleman from Milan. The New Yorker's Richard Brody took note of her chemistry with co-star Noémie Merlant and complimented the actresses for being "relentlessly graceful, endowed with physical aplomb, contemplative insight, and strong emotion". A. O. Scott of The New York Times considered Haenel's performance worthy of an Oscar nomination for Best Actress, and Bilge Ebiri of Vulture described the climax of the film (which features Haenel) as "one of the finest pieces of acting and one of the most moving images I’ve seen in eons." Haenel was nominated for the César Award for Best Actress for her performance, her seventh César nomination.
Adèle Haenel