The sitcom - piloted by the channel earlier this year - is based on Davies's real-life experiences as a teacher.
Man Down sees the Inbetweeners comic play Dan, an immature teacher who struggles with his job and personal life.
A full series of six 30-minute episodes has now been commissioned from Avalon Television, Broadcast reports.
"We're really delighted to work with Greg on a series of Man Down," said Channel 4's acting head of comedy Nerys Evans. "He's created a brilliantly observed world which is laugh-out-loud funny and a perfect fit for Channel 4."
Director Matt Lipsey (Vexed, This Is Jinsy) - who helmed the pilot episode - will return for the series.
44-year-old Davies recently starred alongside US comedian Andy Samberg in hit BBC Three sitcom Cuckoo which wrapped its first series on October 30.
> Andy Samberg's Cuckoo smashes BBC Three comedy record
> Greg Davies: 'I was too much of a wimp for stand-up'
Watch Digital Spy's interview with Greg Davies about his stand-up work below: