The news comes as Australian athletes gear up for the 2012 London Olympic Games.
ASC Chairman, the Hon Warrick Smith AM, said the decision was mutual and failed to give any further indication of why Mr Miller has left after less than 2 years in the top job.
"Matt and I have come to the decision that the time is right for him to move on and allow a new CEO the opportunity to not only lead the ASC but to finish the reform work we have started.
'On behalf of the Board I would personally like to thank Matt for the vital role he has played in commencing the implementation of the Government's new sport agenda.
'Since commencing as CEO in May 2009 Matt has worked tirelessly to ensure the ASC is best positioned to deliver on the Government's vision and is better engaged with Australian sport at all levels," he said.
'The building blocks to ensure the successful implementation of the Government's vision for sport 'The Pathway to Success' have been laid, record new funding for high performance and participation is flowing to sports, the Commission has been restructured to meet the needs of the Government's reform agenda and we now have much stronger relationships with key partners including the Australian Olympic Committee, Australian Paralympic Committee and Australian Commonwealth Games Association, and State and Territory Departments of Sport and Recreation.
The ASC has also announced they would appoint Professor Fricker, CEO of the AIS as the interim CEO – a decision that will draw praise given the proximity to the next Olympic games.
'We will shortly start the recruitment process to replace Matt, but in the interim, AIS Director, Professor Peter Fricker OAM, will lead the Commission in the Acting CEO role.