Guy studied at Wichita State University in Kansas and reached the final of the ATP satellite tournament of Thailand in 1983 . In 1984 he became a professional tennis player and qualified in Auckland for the first time for the main draw of an ATP World Tour tournament with victories over John Evert and Wally Masur . He then made it to the quarter-finals. In 1986 he won the ATP satellite tournament of Yugoslavia and was a semi-finalist in the Challenger tournaments in Budapest and Fukuoka . In 1987 and 1988 he won a double title on the ATP Challenger Tour, and in 1988 he won the single title at the Challenger tournament in Singapore . He won his only title on the ATP World Tour in 1989 in Auckland alongside Shūzō Matsuoka .
Guy played seven singles and three doubles games for the New Zealand Davis Cup team between 1984 and 1991 . His greatest success with the team was participation in the first round of the world group in 1990, which was just lost 3-2 against Yugoslavia . He went to the side of Kelly Evernden in doubles, they were defeated by Slobodan Živojinović and Goran Ivanišević .
After the end of his professional career, he was three times Hessen champion in doubles and twice Hessian runner-up in singles. He worked for the Hessian tennis association and the Offenbach tennis club OTC. In 2007 he became German runner-up over 45. In 2009 he won the bronze medal in doubles at the World Championships in Mallorca in the age group over 50.
New Zealand
Shūzō Matsuoka
John Letts Bruce Man Son Hing