Who was the first tennis player to win all four of the Grand Slam Titles in the same year?

John Donald ("Don" or "Donnie") Budge (June 13, 1915 – January 26, 2000) was an American tennis champion who was a World No. 1 player for five years, first as an amateur and then as a professional. He is most famous as the first player, male or female, and the only American male to win in a single year the four tournaments that comprise the Grand Slam of tennis. Budge was also the second male player to win all four Grand Slams in his career after Fred Perry, and is still the youngest to achieve that feat. He won 10 majors, of which six were Grand Slams (consecutively, male record) and four Pro Slams, the latter achieved on three different surfaces. Budge was considered to have the best backhand in the history of tennis, at least until the emergence of Ken Rosewall in the 1950s and 1960s.