As a 15 -year-old took Sasaki from November 1996 to FIS races in part, from February 1997, in the Continental Cup Far East Cup. His debut in the World Cup he had on 17 February 2003 in the slalom of Shigakogen, in which he could not qualify for the second round. A remarkable feat he achieved on 19 January 2003 at the Lauberhorn in Wengen Slalom, where he completely by surprise behind the Italian Giorgio Rocca drove the # 65 to second place and thus won his first World Cup points.
In the World Cup season 2003/ 04 was a fourth place in Kranjska Gora Sasaki best result, in the season 2004/ 05, a fifth-place finish in Sestriere. He achieved his best giant slalom result 2005 with the 24th place in Sölden. Towards the end of the 2005/06 season he drove in World Cup slaloms two more times to second place in Schladming and Shigakogen. In the following years he succeeded only sporadically, to drive into the points. His last World Cup race, he denied on March 9, 2014 in Kranjska Gora (ranked 22 in slalom ).
Sasaki participated in four Olympic Games and seven World Championships. His best result at a major occasion was the 18th place in the slalom of the Olympic Winter Games 2010. Thrice he was Japanese slalom champion.
- Salt Lake City 2002: 34th slalom
- Vancouver 2010: 18th slalom
- St. Anton 2001: 19 Slalom
- St. Moritz 2003: 38 Super -G
- Åre 2007: 28 Giant Slalom, Super Combined 36th, 54th Super -G
- Schladming 2013: 19 Slalom
- 21 finishes in the top ten, including 3 podiums
Junior World Championships
- Pra Loup 1999: 24 Slalom, 27, Giant Slalom, Super-G 46
- Quebec 2000: 17 Slalom, Giant Slalom 34th, 44th Super -G, downhill 58th
- Verbier 2001: 6 Slalom, Giant Slalom 32
- 3 Japanese championship (slalom in 2007, 2012, 2013 )
- 18 victories in FIS races