In terms of sports biographies, Open by Andre Agassi is considered maybe the best auto-biography in the past 50 years of any kind.
If you want a biography of sports leagues, Loose Balls by Terry Pluto is the best basketball book I've ever read and details the wild history of the ABA. It's probably the most fun I've ever had reading a history book. Also, Lords of the Realm by John Helyar is, in my opinion, the best sports book ever written and a massive history/biography of the MLB.
I'll second Titan by Chernow, as someone wrote earlier. Also, Washington: A Life is a Chernow classic.
River of Doubt by Candice Millard, which details Teddy Roosevelt's journey to map the Amazon after losing the election of 1912, is fantastic.
If you're up for some heavier history, A Path Between the Seas by David McCullough, about the attempt to build the Panama Canal, is an amazing book about the ingenuity and folly of man.