Mandell J. “Mandy” Ourisman, a resident of Palm Beach and Washington, D.C., died Wednesday at his home in Palm Beach with his wife, Mary, by his side. He was 90. He was born on Nov. 10, 1926, at Washington Women’s Hospital, the son of Florence and Benjamin Ourisman. His father started a Chevy dealership in 1921, which grew to be the largest in the country. Mr. Ourisman graduated in 1944 from Riverdale Country School in New York, where he excelled as a halfback, earning the nickname “Snake Hips.” He then attended the U.S. Naval Academy and Georgetown University before joining his father in the automotive business in 1947. With his sons and grandsons, he built Ourisman into a fourth-generation automobile business with more than 36 franchises in Virginia and Maryland. Mr. Ourisman had three sons from his marriage to his first wife, Jane Elsie Miller, which ended in divorce. He later married Betty Lou; and for the past 24 years to the Hon. Mary Martin Ourisman, who survives him. He accompanied Mary as she served abroad as U.S. ambassador under the G.W. Bush administration, representing the United States in Barbados, Antigua and Barbuda, St. Lucia, St. Vincent and the Grenadines, St. Kitts and Nevis, Grenada and Dominica. The couple served as chairman and chairwoman of the International Red Cross Ball in Palm Beach, where they were members of The Mar-a-Lago Club, Club Colette, and The Breakers. In addition to his wife, he is survived by his sons, David J., John M. and Robert B. Ourisman; stepsons, Daniel L. and Thomas E. Korengold, and Colby M. Johnson; a stepsister, Wallace Annenberg; 16 grandchildren, and three great-grandchildren.