Newport Beach-based John Laing is the second-largest privately held home builder in the US.
Its acquisition marks the first US venture by Emaar, one of the world's largest developers.
"This agreement will provide Emaar with an important gateway into the US real estate market," Mohamed Ali Alabbar, Emaar's chairman, said in a statement on Thursday.
Some analysts suggested the deal, coming at a time when the real-estate market is slowing, may signal growing interest by foreign companies in the sector that is expected to see further consolidation after a five-year boom.
"It certainly bodes well for the long-term real estate market in this country, because you have a foreign company investing in a US-based home builder," said Patrick Duffy, managing director of industry market research firm Hanley Wood Market Intelligence.
The deal has been approved by the federal Committee on Foreign Investment in the US.
John Laing Homes had revenue of $1.6 billion last year on 2,891 residential closings. It ranked 20th among US builders and owns or controls 150,000 undeveloped lots.
The deal will give the company resources to grow beyond its principal markets in California and Colorado, Larry Webb, John Laing's chief executive, said in a statement.
He said the former subsidiary of British construction company John Laing PLC had not been pursuing a sale. Emaar approached him late last year, Webb said.
Emaar is building Burj Dubai, the
world's tallest skyscraper
Webb and other top executives have agreed to multi-year contracts and will continue to run the company, which will become a division of Emaar.
Emaar builds luxury housing and commercial developments throughout the world, with projects in Egypt, Turkey, India, Saudi Arabia, Morocco and Pakistan, among other markets.
Among its best-known projects is the Burj Dubai, which upon its completion in 2008 will be the world's tallest skyscraper.
The developer generated $2.3 billion in revenue last year and posted profit of $1.3 billion.