Heidi soon began a relationship with British singer Seal, who was present for Leni's birth and adopted her when she was five years old.

[5][6] Raised in Los Angeles, she graduated from Pacifica Christian High School in 2022, and enrolled in college in New York City, studying interior design.

[7][2] At the end of 2020, Klum made her modeling debut on the January/February 2021 cover of Vogue Germany, appearing alongside her mother wearing colorful synchronized pantsuits.

[11][12] Klum appeared on various other magazine covers before turning 20, including Harper's Bazaar Kazakhstan, Hunger, Flaunt, and Rollacoaster, and was in advertising campaigns for brands such as Dior and Fila.

[13][14] Klum appeared as a guest judge in the semifinals of her mother's show Germany's Next Topmodel in 2022 and returned in the finals in 2023.