Dean Macey started out in athletics as a triple jumper but graduated up through the octathlon to settle on the decathlon. He was also on the books of Arsenal F.C. as a youngster but gave up football to train for the World Junior Championships in 1995.
Macey's major breakthrough was when he won silver medal at the 1999 World Championships in Athletics in the Olympic Stadium, Seville, Spain with a personal best of 8556 points finishing behind gold medallist Tomas Dvorak of the Czech Republic.
The following year at the 2000 Summer Olympics, Sydney, Australia, after an injury ravaged year, Macey recorded another personal best score of 8567 points but could only finish fourth. The title was won by Estonian, Erki Nool but only after an appeal when earlier in the day the referee over ruled his field judges and ruled out Erki's discus throw of 43.66 metres. The appeal was successful and the Estonian took gold ahead of the Czech, Roman Sebrle and American Chris Huffins.
Macey was back amongst the medals at the 2001 World Championships in the Commonwealth Stadium, Edmonton, Alberta, Canada, improving on his personal best yet again, with 8603 points finishing with the bronze medal, once again behind Tomas Dvorak (gold medal), and Erki Nool (silver medal).
Injuries made Dean miss the 2002 Commonwealth Games held at the City of Manchester Stadium, Manchester, England and all other major competitions until making his comeback at Hexham, England, July 2004.
His score in Hexham of 7842 points was, purposely, just enough to meet the B qualifying standard of 7700 for the upcoming Summer Olympic Games.
At the 2004 Summer Olympics in Athens, Greece Dean performed well, in view of the recent years away from competition, but with a possible medal in his grasp, a below par pole vault and javelin throw once again left him in fourth place at an Olympic competition behind Roman Sebrle (gold) and Bryan Clay (silver).
At the 2006 Commonwealth Games, despite still nursing some injuries, Macey led after the first day with a personal best of 15.83 metres in the last round of the shot put. Over the course of the second day, that gap was reduced and overhauled by the Australian Jason Dudley because of injury-hampered performances in the 110m hurdles and the javelin. Going into the final event, the 1500 metres, Macey needed to score 38 points more than Dudley to claim gold. He completed the event in 4:34.22, which gave him the gold medal by 69 points. Dean finished with a total of 8143 points, ahead of Maurice Smith (silver) and Jason Dudley (bronze).
Macey was the inaugural winner of BBC Sports Personality of the Year Young Personality in 1999.