The former X Factor runner-up's collaboration with Flo Rida sold 121,000 copies to top this week's chart ahead of Girls Aloud.
It is also the fourth time Flo Rida has topped the UK chart.
Murs said of his achievement: "Wow! My fourth number one single, I am so happy I can't even begin to tell you! Thanks so much to everyone who bought 'Troublemaker', I hope you all like the album too!"
Girls Aloud's comeback single 'Something New' enters at two, scoring their 16th top five hit.
One Direction slip two places from last week's top spot to three with 'Little Things', while Labrinth is a non-mover at four with 'Beneath Your Beautiful'.
Alicia Keys wins her sixth UK top five single, with 'Girl on Fire' landing at five after having performed it on last week's X Factor results show.
Psy climbs back one place to six with 'Gangnam Style', while Gabrielle Aplin's cover of 'The Power of Love' slips two to seven. Robbie Williams drops two spots to eight with 'Candy'.
Bruno Mars slips six places to nine with 'Locked out of Heaven', while Rihanna drops one place with former number one 'Diamonds' to ten.
Christina Perri climbs six places to 13 with 'A Thousand Years', following its use in the latest Twilight movie.
Rudimental's collaboration with John Newman and Alex Clare 'Not Giving In' is new at 14.
AC/DC's 1980 classic 'Back in Black' enters at 27, following the band's back catalogue being made available on iTunes for the first time earlier this week.
The song reaches a new peak after not reaching the Top 40 on its original release. 'Highway To Hell' also creeps in at 40, having also not reached the Top 40 in 1979.
Rihanna scores a new entry at 36 with her David Guetta collaboration 'Right Now', following the release of new album Unapologetic.
DJ Fresh also re-enters the Top 40 with 'Gold Dust' at 38.
Watch the video for 'Troublemaker' by Olly Murs below:
Source: Official Charts Company
> This week's albums chart