Robert E. Linton, a prominent Wall Street executive who led the swashbuckling investment bank Drexel Burnham Lambert in the years before it imploded in scandal but who was largely untainted himself, died in Manhattan. He was 90. The cause was heart failure, his son Jeffrey said. During his tenure atop Drexel in the early 1980s, Mr. Linton oversaw the firm’s rapid expansion into one of the nation’s biggest — and most profitable — investment banks. Although Mr. Linton was a board member during much of that period, he was no longer C.E.O. And Mr. Linton, who was never accused of wrongdoing in the case, had previously denounced some of Wall Street’s excesses. Robert Edward Linton was born on May 19, 1925, in Manhattan. After graduating from Phillips Exeter Academy in New Hampshire and forgoing college, he enlisted in the Army in 1943 and served in World War II, attaining the rank of second lieutenant in the Army Air Forces. After the war, Mr. Linton returned to New York, raising his family in Rye. At the time of his death, he had homes in Manhattan and Purchase, N.Y. Besides his son Jeffrey, he is survived by his wife of 63 years, the former Margot Tishman; two daughters, Roberta L. Bennett and Elizabeth M. Linton; another son, Thomas; a sister, Marion Benson; and five grandchildren.