The first professional men's tournament was held in 1889 in the US. It was named the SAP open, is the second oldest US tournament in total and is still held today. Names from that tournament include the champion, William H Taylor, and Valentine Gadesden and Charles Yeats, so these must have been among the first professional tennis players.

The first official professional tennis tour was held in 1926. It was organised by the American sports agent CC Pyle.

However, most of the major international events were only open to amateurs. It wasn't until 1968 that the events became open to all - which in effect, would soon mean that only professionals would compete in them. Before 1968, there was no financial incentive for winning a tournament such as Wimbledon, for example. However, the professional events did offer cash, which meant that a number of amateur players became professionals in order to win money ... Which then meant that they couldn't play in events like Wimbledon. So the rule had to be changed.