After graduating from Columbia Law School in 1957, Donald R. Osborn joined Sullivan & Cromwell, became a Partner in 1964 and Senior Counsel in 1997. As an associate, he was engaged in tax matters and estate planning. Upon becoming Partner, he was primarily involved with the affairs of individual clients of the office, leading to extensive involvement with charitable foundations, horse racing, art collections, higher education, private investment partnerships, cable television, coal mining, newsprint journalism and the beer and wine industries. His experience enabled him to advise clients on a broad spectrum of matters, not just tax law.
His practice included advising domestic clients such as McKinsey & Company, Inc., The National Gallery of Art, The Andrew W. Mellon Foundation and Paul Mellon’s Rokeby Stables. He also represented Wm S. Paley and became a director of CBS. He was also involved with The White Burke Miller Center of Public Affairs, the Museum of Broadcasting and Kirkland and Hamilton Colleges, as well as many private foundations.
Internationally, he travelled extensively, representing individual clients in Bermuda, Europe and Asia, and the companies they owned, such as San Miguel in The Philippines and Spain and Averys of Bristol, a wine merchant company in England, among others.