Dean completed his first triathlon in August 1981. He won the first race he entered and has been hooked on the sport ever since. He competed as a professional triathlete from 1982-1986 alongside the early legends of the sport—Dave Scott, Mark Allen, Scott Molina and Scott Tinley. He won the first Wildflower triathlon in 1983, and again in 1986. He won the first USAT Long Course championships in 1983, was 8th in Hawaii in October 1982 and won several other pro races in those years. He was on the first cover of Triathlete Magazine and graced its cover one other time. He also won the first USTS West Coast triathlon series in 1982, the popular series’ first year.

Dean started practicing law and raising a family beginning in 1987 and only competed a few times in the next 15 years, but followed the sport during those years and never gave up his subscription to Triathlete Magazine. He began competing heavily again as an age grouper in 2003 and competed in around 80 races from 2003 to 2010. During that time, he was ranked by USAT as the top male athlete in his age group in the country 3 times. He once held 10 Tri-California age group records (including Alcatraz, Wildflower, Pacific Grove and Treasure Island), won his age group in the U.S. Long Course National Championships in 2004, the U.S. Short Course Nationals in 2008, and the ITU Short Course World Championships on the Gold Coast in Australia in 2009. He competed in several Ironman races, winning his age group in Arizona in 2005 and was third in his age group in HawaiiIronman World Championships in 2008.

Dean has 3 children who all swam for D1 schools, with 2 of them, Greg and Shelley, highly successful members of Cal Tri and who both posted the fastest swim times at Collegiate Nationals several times.

Dean is a USAT Level I coach and a USAT Level I race director. Cal Berkeley has won several national championships since he started coaching in 2013. He was Cal Club Sports Coach of the Year in 2018.