Michael recently told the Big Issue that he had stopped his drug-taking lifestyle and not used cannabis for "well over a year-and-a-half".George Michael's Symphonica has beaten Kylie Minogue's Kiss Me Once to the top of the UK album chart.
It is the former Wham! star's seventh solo number one.
"Thank you so much... it's so nice to be able to savour this wonderful moment. I am a lucky man," Michael told OfficialCharts.com.
His album sold just over 20,000 copies more than Minogue's. Meanwhile, Duke Dumont claimed his second Number one single with I Got U FT Jax Jones.
His last - Need U (100%) FT A*M*E - kept Ding Dong The Witch is Dead off the top of the album chart following the death of Margaret Thatcher.
The Human League landed their highest charting single in almost 20 years, following a campaign by fans of Aberdeen Football Club.
The group's 1981 Christmas Number 1, Don't You Want Me, has become a fan anthem and climbed to number 19 today following Aberdeen's Scottish League Cup win last weekend.
Charity singleSymphonica is Michael's first new album in nearly 10 years, and was recorded during the singer's 2011/12 world tour.
Route 94's My Love FT Jess Glynne kept its place at number two, while John Legend's ballad, All Of Me, climbed three places to third spot.
Pharrell Williams' Happy and last week's number one, Tsunami (Jump) by Dvbbs, Borgeous and Tinie Tempah, rounded out the top five.
Little Mix's official single for this year's Sport Relief, a cover of Cameo's Word Up, was the second highest new entry at number six.
On the album chart, Pharrell Williams' GIRL remained at number three, Paloma Faith's A Perfect Contradiction dropped two places to number four, and last week's number one, Elbow's The Take Off And Landing Of Everything, fell to number five.