Heiner debuted as an exclusive for Louis Vuitton's S/S 2021 fashion show and opened the next season's F/W 2021 show. By the S/S 2023 season she had walked for Chanel, Alaïa, Fendi, and Schiaparelli.[3] She has also walked for Tory Burch, Altuzarra, and Proenza Schouler, as well as working consistently with Chanel ever since Virginie Viard became the creative director.[4]
In June 2023, Heiner appeared in a Vogue editorial set in Liguria, Italy, alongside models Nora Attal, Vittoria Ceretti, Paloma Elsesser, and Anok Yai.[5]
Heiner appeared on the cover of the December 2023/January 2024 issue of Vogue France.[6] Heiner is ranked as one of the "Top 50" models in the industry by models.com and was nominated for the "Model of the Year" award in 2023.[7][8] Vogue chose Heiner as one of the top 11 models of the S/S 2023 season, noting her sharp cheekbones and her runway walk as some of her trademarks.[3]