Mr Smith, who succeeds Bill Ruprecht, has been president and CEO of the Madison Square Garden Company since February 2014. There he oversaw the overall strategy and day-to-day operations of MSG Sports, MSG Media, and MSG Entertainment.
The Harvard Business School graduate's previous roles extensive experience in the hotels, resorts and entertainment industry, CEO of Reed Elsevier's US business-to-business division, Reed Business Information, and President, Local Media at Cablevision Systems Corporation.
Sotheby's have also decided to separate the post of chairman from CEO and have appointed Lead Independent Director Domenico De Sole to succeed Ruprecht to chair the Board.
Mr Ruprecht steps down after 35 years with company, the past as CEO. He also became chairman in December 2012.