Friday's move came as a surprise to many observers and throws into question Winterstern's ambitions to acquire Millennium/Nu Image.
This morning a spokesperson said it was 'business as usual' at the Los Angeles-based company. A successor is expected to be named within the next few weeks.
Winterstern will remain the largest shareholder and will reacquire Capital Entertainment - the company he merged with First Look when he arrived in July 2005 - and has established a production agreement through Capital with First Look.
Capital Entertainment will provide strategic advice to investment organisations and media companies, including First Look.
Winterstern was in the process of implementing a grand expansion strategy at First Look Studios. In less than two years the entrepreneur made key appointments, bringing in former Miramax International chief Stuart Ford to head sales arm First Look International, and former Paramount Classics co-head Ruth Vitale to oversee domestic distribution division First Look Pictures. Ken DuBow oversees First Look Television.
Under Winterstern's short tenure, First Look Studios bought DEJ Productions and video distributor Ventura Distribution, secured an $80m credit line with Merrill Lynch, and bulked up the release slate with upscale titles such as An American Crime and the upcoming The Loss Of A Teardrop Diamond.
'Henry Winterstern played a leading role in transforming First Look into an independent, fully-integrated entertainment studio, and he remains the largest individual shareholder of the company,' a statement from the board of directors read.
'His broad understanding of the industry and his demonstrated skill as a deal maker and strategist will serve the future clients of Capital Entertainment well and we are pleased that he will continue to be a resource to First Look.'