Who was the first male player to win all four Grand Slam titles in one year?

The first male player to win all four Grand Slam titles in one year was Don Budge. He achieved this feat in 1938. Here are the steps to find this information:

1. Understand the question: The question is asking for the first male tennis player who won all four Grand Slam titles (Australian Open, French Open, Wimbledon, and US Open) in a single calendar year.

2. Research: Look up information on the history of Grand Slam winners in tennis. This could involve searching for a list of Grand Slam winners by year, or specifically looking for information on the first player to win all four in one year.

3. Find the answer: Through research, you would find that Don Budge was the first male player to win all four Grand Slam titles in one year, achieving this in 1938.

4. Verify: Cross-check this information with multiple reliable sources to ensure its accuracy.

5. Respond: After confirming the information, respond to the question with the answer: Don Budge.