By Callum Borchers Globe Correspondent

Billionaire casino magnate Sheldon Adelson has consummated his new alliance with presumptive Republican nominee Mitt Romney by donating $10 million to Restore Our Future, a super PAC backing Romney’s candidacy.

Adelson, a Dorchester native, has been the most generous donor of the presidential election, but none of the $25.3 million he and his wife, Miriam, had given to conservative candidates and committees through April had gone toward aiding Romney. In fact, most of Adelson’s money had been directed at a super PAC supporting Newt Gingrich, one of Romney’s GOP primary opponents.

But with the former House speaker out of the race, Adelson met with Romney late last month in Las Vegas and pledged to back him. The $10 million gift to Restore Our Future, reported first by The Wall Street Journal, is the first fulfillment of Adelson’s promise.

Adelson, who is Jewish, reportedly wanted assurance that Romney would support Israel more strongly than President Obama. Over the years, Adelson has given $100 million to Taglit-Birthright Israel, which sponsors trips to Israel for young Jews.

The chief executive of resort-casino giant Las Vegas Sands is worth almost $25 billion, according to Forbes magazine, a sum that makes him the nation’s seventh-richest person.