Born in Cambodia, Ratha spent the first few years of his life traveling throughout Southeast Asia before moving to Dobbs Ferry, New York. After attending Clark University, Ratha joined his brother in Maine exporting sea urchin to Japan where he remained for two years. His time spent in sea urchin exportation was tangentially related to the passion Ratha always had for cooking, and he frequently worked with restaurant owners and chefs. With his interest in the restaurant industry piqued, Ratha moved to Waltham, Massachusetts to join The Elephant Walk restaurants. After successfully working his way up through the front of house, Ratha moved to Manhattan where he eventually became general manager and wine director of Fleur de Sel. Eager to have his own restaurant offering a menu that reflected the food of Southeast Asia that he loved to prepare in his own kitchen, Ratha opened Kampuchea in the Lower East Side. Soon after opening, Ratha realized the fresh sandwiches on the menu were the biggest sellers, and he also recognized that the sandwiches could stand as a singular dining focus. Along with his friend Ben Daitz, Ratha opened Num Pang in Union Square in March 2009. Since then, they have continued to grow, opening up a flagship location in the up-and-coming NoMad neighborhood, as well as Midtown East, Chelsea Market Chelsea Market, Times Square, Hudson Eats at Brookfield Place, FiDi South and FiDi North.