In 1971, Wilkerson won the ATA Men's Singles Championship. This accomplishment was extremely impressive because he started playing late in his youth. Born in San Antonio, Texas, Wilkerson was a senior in high school when he first picked up a tennis racket. John's brother and his friends played tennis on weekends and they frequently tried to convince him to come along. He refused to join them for many months.

However, he fell in love with the sport the one day in 1957 that he decided to go with them to the tennis courts. The next week he tried out for his Wheatley High School tennis team and, because he was a natural athlete, beat all of the players on the team. Incredibly, Wilkerson went on to win district and state titles in singles and doubles that year. He was given a tennis scholarship to Prairie View A&M. However, he dropped out of school to join the US Army. He later attended Texas Southern University (TSU), and, in 1972, won the Southwest Athletic Conference (SWAC) Singles and Doubles Championship.

After graduating from TCU, Wilkerson became the Tennis Director at MacGregor Park in Houston, Texas and developed a passion for teaching young people about tennis and life. In 1977, he started coaching two 11 year olds named Zina Garrison (2009 BTHF Inductee) and Lori McNeil (2011 BTHF Inductee) at the MacGregor Park tennis courts in Houston, Texas. Wilkerson would coach these players throughout their tennis career and become one of the best known black coaches in pro tennis. Under his tutelage, these players would go on to become two of the best black professional tennis players in history.

In 1981, Garrison became the first African American to win the Wimbledon and US Open Junior Titles. That year she became the number one 18 year old player in the world. In her first tournament as a professional, the 1982 French Open, she had an amazing run to the quarterfinals where she was beaten by 2000 ITHF Inductee Martina Navratilova. On November 20, 1989, Garrison reached a career high singles ranking of number 4 in the world. She also reached a career high doubles ranking of number 5 on May 23, 1988. On July 4, 1988, McNeil reached a career high singles ranking of number 9 in the world. In addition, on November 9, 1987 she reached a career high doubles ranking of number 4 in the world.

Wilkerson is a board member of the Houston Tennis Association and is currently the Tennis Director for the Zina Garrison All Court Tennis Academy. In this role, he has helped more than 100 youth receive college scholarships. He was inducted into the Texas Tennis Hall of Fame in 2002 and the Texas Black Sports Hall of Fame in 2009.