In March 2006 Karoline Leth became producer at Tju-Bang Film. In March 2007 Leth became the Managing Director of the company. Tju-Bang Film produced among others THE MONESTARY directed by Pernille Rose Grønkjær, MECHANICAL LOVE directed by Phie Ambo and YOUNG MAN FALLING directed by Martin de Thurah.
In 2008 Tju-Bang Film changed name into SF FILM PRODUCTION given the fact that Swedish Film Industry (SF) bought Tju-Bang Film in 2005 and thereby is the financially strong partner in the company. SF FILM PRODUCTION is the Danish production unit of Swedish Film Industry. The goal of SF FILM PRODUCTION is to produce both feature and documentary with high artistic value. In 2008 Leth released DANISH DYNAMITE a documentary directed by Mads Kamp Thulstrup and Carsten Søsted about the Danish National Football Team. At the same time Leth co-produced ARN I and ARN II – the feature films directed by Danish director Peter Flinth based on the novels by Jan Guillou. In 2007 Leth produced the documentaries CLARITY directed by Ole Bendtzen, THE FACE OF PASSION directed by Judith Lansade and THE CLASS directed by Ida Marie Darger.
From February 2004 until February 2006 Karoline Leth was CEO and producer at Zentropa Real - the documentary division of Zentropa. Leth produced 6 films under Lars von Trier’s concept, DOGUMENTARY- among these RAW YOUTH directed by Margreth Olin and GET A LIFE by Michael Klint. Leth also produced THE WEEDS OF LUSAKA directed by Henrik Grunnet. Autumn 2005 Leth launched GUERRILLA GIRL directed by Frank Piasecki Poulsen at IDFA and the film has since that been traveling around the world on documentary festivals – latest at Silver Docs Festival in the US.
Since 2002 Leth has been distributor of director Jørgen Leth's foreign sales.
As for 1999 to 2004 Leth was a producer, teacher and a co-ordinator at The National Film School of Denmark, Documentary Department, where she among others financed and produced 25 documentaries from the 3rd world, in co-operation with the Royal Danish Ministry of Foreign Affairs / Danida. Among these GROWING UP IN A DAY directed by Phie Ambo which was premiered at IDFA 2003. In the same period Leth also produced 18 graduation documentary films at the film school.
Karoline Leth has been as well a performing jazz-singer and music instructor and is still working on developing concepts for theatre.