Born in Waihi, New Zealand, Dean is the son of Waimata dairy farmers Peter and Valerie Dean. Locally known as the "Grasshopper", started cycling when he was just a child, beginning at the local BMX club in, where he had success with two 3rd-place finishes in the New Zealand Championships. Dean tried his hand at many sports before moving onto triathlon, which he enjoyed. From triathlon, Dean fell in love with cycling, where he represented New Zealand in road and track disciplines. In 1997, Dean got his chance to race in the US with the Shaklee team and the Mercury cycling team in 1998.
Career
US Postal
In 1999, Dean signed to the now-defunct US Postal Service Pro Cycling Team, whom he rode for until 2001, gaining experience from racing in Europe. He managed his first European victories with 2 stage wins in the tour of Britain. After having ridden in a team based around Lance Armstrong Dean went looking for new opportunities. He got them by joining in 2002. However, his joy was short-lived when Dean broke his leg in March 2002 and was out for three months. He took a stage win in the short stage race Tour de Wallonie taking the leaders jersey & holding on to win the overall race beating some of the world's best riders to the victory including a great tussle with Italy's star rider Michele Bartoli.
Credit Agricole
In 2004 he signed to as a lead-out man for sprinter Thor Hushovd. He finished 8th behind stage winner Tom Boonen in Stage 6 of the Tour de France. He missed the 2005 edition of the Tour due to an injury incurred in the 2005 Giro d'Italia. He later returned for the 2006 edition. The 2007 cycling season started well with Dean winning the New Zealand Road Racing Champion title. This win entitled Dean to represent and wear the black and white New Zealand national cycling jersey whilst racing in all international road-racing events throughout the 2007 season. He continued to ride for the French-based team Crédit Agricole. During the 2007 Tour de France, Dean was known for his role of lead-out for Thor Hushovd. Hushovd later said in interviews that Dean was "the best lead-out man in the world." Dean's last public appearance wearing the Crédit Agricole jersey was the 2007 Mt Maunganui criterium race, held on 27 December 2007. He won the elite category.
Slipstream-Chipotle
From 2008 to 2011, Dean rode for Jonathan Vaughters' team. He once again started the year by winning the New Zealand national Road Racing Championship, held in January. He recorded six top-ten finishes in the 2008 Tour de France, with a best performance of fourth in stage 14. His overall classification was 110th, and 9th in the points competition. In 2009, during the 13th stage of the Tour de France from Vittel to Colmar he, along with Óscar Freire of got shot by an air rifle. He got shot in the thumb but was able to continue with a largely swollen hand where he eventually finished 112th on the stage. In completing the Tour de France, Dean became the only rider to start and finish all three grand tours during the 2009 season. During the finish of stage 11 from Sisteron to Bourg les Valence in the Tour de France Dean was involved in a highly publicised incident with Mark Renshaw, who repeatedly headbutted Julian Dean, who he believed had come across into his lead out. Subsequently, Renshaw was disqualified from the Tour de France.
Dean is married with two children. During his time in New Zealand, Dean, is based in Rotorua, New Zealand where he hopes to eventually be based permanently. In 2010 Dean competed in the Singlespeed Mountain Biking World Championships.
