Williams will share the president title with founding partner John Penotti. GSF co-founder Fisher Stevens will no longer have an active day-to-day role in the company but will continue to produce selected projects.
GSF established a West Coast office in 2006 and put Williams in charge and more recently hired Amy Beecroft as head of GreeneStreet Films International and Eric Spiegelman as an exclusive consultant to develop digital, new media and internet strategy.
Williams and Hogan have been working closely with GSF president John Penotti and the next stage in the company's strategy will be unveiled in the coming months.
In addition to his new duties as co-president Williams will continue to oversee production and development out of the company's Los Angeles office, while Hogan will oversee all operational and financial aspects from the New York City offices.
'Tim has been a key architect for GreeneStreet's growth and success over the years and I'm thrilled he is growing his role and sharing the title of president with me,' Penotti said. 'Mike has been an extremely valuable consultant to GreeneStreet for several years and we're excited he's joining the company in a fulltime capacity.
'We will miss Fisher's incredible contributions to our day-to-day operations but are very supportive of his decision to pursue new opportunities, some with us as a producer.'
Hogan has served as a consultant for GSF since 2007. From 1999 to 2007 he was partner and COO at the New York-based Hart Sharp Entertainment.
Prior to joining GSF Williams spent several years running a London-based theatre company.