Castle won three ATP titles in men’s doubles and one title on the Challenger tour. From 2000 to 2010 he was a presenter on the Breakfast television station GMTV. Castle has participated in the reality TV series Strictly Come Dancing and 71 Degrees North. From 2003 to 2013 he was a guest host and panelist for the television series The Wright Stuff. Castle has also been a TV tennis commentator for Wimbledon, Wimbledon 2Day, Tennis: Barclays ATP World Tour Finals, and Aegon Championships.