• 2006-2007: Selected as player/captain Unite d States Fred Perry Cup Team
• Fred Perry Cup World Champions in 2006 and finalist in 2007
• 2003-2005: Selected as captain of United States Leon Dubler Cup Team
• 2000, 2004, 2005: Dubler Cup World Champions
• 2001-2003: Ranked No. 1 in the United States by the USTA in Men's 45 and older singles
• 2001-2002: Ranked No. 1 in the world by International Tennis Federation
• Two time ITF World Champion in Men's 45 and older doubles
• 2001: Professional Tennis Registry International Player of the Year
• 1991, 1992, 1994, 1996: Selected as player of United States Italia Cup 
• 1993 and 1994: United States Professional Tennis Assoc. National Player of the Year
• 1993: Played professional World Team Tennis for San Antonio Racquets 
• 1990: Featured in Sports Illustrated, Faces in the Crowd, for being the only player ever to win four national USTA doubles titles with four different partners on four different surfaces in the same year
• Ranked No. 1 in the United States in singles and doubles in Men's 35, 40, and 45 and older age divisions during career
• Earned over 50 national and international championships in singles and doubles
• Coached privately at professional level for four years and also coached three college all-americans including two-time NCAA Div II singles champion Rebecca Huereque and NJCAA singles and doubles champion Mike Castillo

During the 2010-2011 season Castillo led women's to the conference regional tournament. OLLU's tennis teams also hold the highest GPA out of all athletic teams on campus as Castillo stresses the importance of education to his student-athletes.