Former Valve economist Yanis Varoufakis has quit as Greek finance minister just six months after taking the job.

Hats off.

Varoufakis, an economics professor based in Athens, joined Valve in March 2012 as a consultant after Gabe Newell emailed to describe the problems his company ran into as the virtual economies around games such as Team Fortress 2 and Dota 2 saw explosive growth.

He joined Greece's government late 2014 to try to help the country recover from economic crisis, and quickly established a reputation for being a flamboyant and outspoken critic of his country's creditors.

He resigned today just hours after Greek voters backed his call to reject creditors' demands for more austerity in a referendum.

"Soon after the announcement of the referendum results, I was made aware of a certain preference by some Eurogroup participants, and assorted 'partners', for my... 'absence' from its meetings; an idea that the Prime Minister judged to be potentially helpful to him in reaching an agreement. For this reason I am leaving the Ministry of Finance today," he wrote in a defiant blog post.

"I consider it my duty to help Alexis Tsipras exploit, as he sees fit, the capital that the Greek people granted us through yesterday's referendum.

"And I shall wear the creditors' loathing with pride."

Greek banks are running out of money and on the verge of collapse, and it is feared Greece is heading for an exit from the euro.

As for Varoufakis, he is yet to indicate his next move. Perhaps a return to Valve beckons?