WASHINGTON — Sambonn Lek, bartender at the St. Regis hotel near the White House, has shaken and stirred for movers and shakers since the Carter administration. At 66, he leads a disappearing fraternity: barkeeps who know their regulars’ names and favorite cocktails, and when they drink so much of the latter that they forget the former, find them a ride home.

When it’s quiet, he breaks out his repertoire of magic tricks, which in the days before the fire marshal stepped in included “breathing fire” by blowing a mouthful of spirits past a flame.

Mr. Lek’s greatest act, though, is performed daily in his native Cambodia, with the help of his affluent patrons. He is a Vietnam-era refugee turned philanthropist, collecting spare change and big checks from customers to fund Sam Relief, which builds schools, digs wells, and provides food, clothing and medical and school supplies in his native Cambodia. Since 2000 his nonprofit has built 27 schools, dug nearly 400 wells, delivered 290 tons of rice and awarded 120 scholarships to Cambodian schoolchildren.

Mr. Lek, who said he escaped Cambodia’s genocide and poverty because America opened its doors to him, believes that human generosity transcends politics. Over two decades, his patrons of both parties have proved him right.