[5] At the Japanese Track and Field Championships he was the runner-up in the 10,000 metres and subsequently represented Japan at the 2002 Asian Games, taking sixth place.
He performed to a lower standard in 2005, having seasonal highlights of a fifth-place finish in the 10,000 m Japanese trials and 16th at the Chicago Marathon.
[9] At the 2007 IAAF World Road Running Championships he broke the Asian record for the half marathon with a time of 1:00:25 hours.
This brought him ninth place overall, but he was one of only two non-African-born runners to finish in the top ten (alongside Marilson dos Santos).
[5] He was the best non-African performer in the marathon at the 2009 World Championships in Athletics, taking sixth place in the rankings.
[12] Sato began 2010 at the New Year Ekiden and he moved his team, Chugoku Electric, up in the rankings by winning his 22.3 km stage.
He struggled in the 23 km stage of the 2012 New Year Ekiden and subsequently missed races due to injury.