Born in Herne, North Rhine-Westphalia,[1][2] Leonie entered the adult industry in September 2005, at the age of 19 years.

[3] In 2006, she became an exclusive actress for the company Videorama, for which she made her own series called Leonie.

[3] In 2007, she appeared in the music video "Lover's Lane" for the German horror punk band The Other.

[2][3][9] In a 2011 interview, she said that she was disillusioned with the porn industry, that she would not do it again, and that she believed to have been deliberately infected with chlamydia by a jealous colleague.

[3][10] Saint played a minor role in the 2009 film Männersache [de], directed by Mario Barth;[1] she had previously been the leading actress and main subject of an eponym 2007 short film, Leonie Saint, directed by Jana Debus and showed at the 53rd International Short Film Festival Oberhausen.