But the move carries risks, as gamers can be fickle. Although the Lego-like multiplayer game is currently the top paid app for the iPhone and Android devices in the U.S., today's popular hit could be tomorrow's dud. The maker of the much obsessed-over "Candy Crush Saga," for example, rode the game's popularity to go public this year, only to see its stock falter.
In addition, the founders of Mojang, the Swedish company behind "Minecraft," aren't staying with Microsoft. That could raise questions about Mojang's ability to create another big hit.
Then again, a big hit was not what co-founder Markus "Notch" Persson was after when he created the game, according to a blog post Monday from Mojang and a note from Persson himself on his website.
"It certainly seems like the founders of 'Minecraft' didn't want to continue forward," Gartner analyst Brian Blau said. "It was something too big for them. 'Minecraft' is best in the hands of somebody who can take it in the direction it needs to go for the user."
Microsoft has made mobile phones and Internet services priorities for the company as its traditional businesses - Windows and Office software installed on desktops - slow down or decline. With "Minecraft," Blau said, Microsoft gains a new type of customer - mobile players.
"Minecraft" is an "open world" game in gamer lingo, meaning it has no plot or outlined objectives. Players can explore and create virtual worlds built from blocky 3-D objects - thus the frequent Lego comparisons.
"It can also be about adventuring with friends or watching the sun rise over a blocky ocean. It's pretty. Brave players battle terrible things in The Nether, which is more scary than pretty. You can also visit a land of mushrooms if it sounds more like your cup of tea," Minecraft's website explains.
Besides iPhones and Android devices, the game is available on Windows, Macs, Microsoft's Xbox and Sony's PlayStation. Microsoft said it will continue to make "Minecraft" available on all those platforms after the deal closes, expected this year.
With an all-ages "E'' rating, the game has been downloaded 100 million times on personal computers since its debut in 2009, and it's the most popular online game on Microsoft's Xbox console.
Microsoft, which released the first Xbox in 2001, also owns the blockbuster "Halo" video game franchise. Unlike "Halo," though, "Minecraft" is especially popular with younger gamers whose parents might not be comfortable with them going on wild alien shootouts.
Microsoft is not alone in trying to reach that audience. Activision Blizzard Inc., the maker of the "Call of Duty" shooter series, also makes "Skylanders," a kids' video game that's played using toy figures.
Now, it will be Microsoft's job to keep Minecraft's loyal fan base happy. It's something raised any time big, established corporations buy little, much-loved independent companies. It happened when Facebook bought photo-sharing app Instagram in 2012 and more recently when Amazon agreed to buy Twitch, the online network that lets people watch live and recorded footage of others playing video games.
"Change is scary, and this is a big change for all of us. It's going to be good though. Everything is going to be OK," Owen Hill, Mojang's "chief word officer," wrote in a blog post Monday.
"Minecraft will continue to evolve, just like it has since the start of development. We don't know specific plans for Minecraft's future yet, but we do know that everyone involved wants the community to grow and become even more amazing than it's ever been," he continued.
The acquisition will help Microsoft expand its gaming division. Besides "Halo," it includes the "Forza" racing game. In a statement, Microsoft CEO Satya Nadella said that with "Minecraft," Microsoft is getting "an open world platform, driven by a vibrant community we care deeply about, and rich with new opportunities for that community and for Microsoft."
Blau said it helps that Microsoft knows games.
"It's got the Xbox," he said. "So overall ... it's a good move and a good fit because they have experience in the game industry."