The first professional golfer to win the Grand Slam is Bobby Jones. He achieved this remarkable feat in 1930 by winning all four major championships: the U.S. Open, the U.S. Amateur, the British Open, and the British Amateur in the same calendar year. Bobby Jones is regarded as one of the greatest golfers in history, and his accomplishments greatly contributed to the popularity and development of the sport. His legacy continues to inspire golfers all over the world, illustrating the heights of excellence in golf.