His best results on the world circuit until recently were runner-up finishes at the 2008 Singapore, 2007 Swiss, and 2008 Indonesia Open.

In September 2008, Santoso won the Chinese Taipei Open after defeating Roslin Hashim from Malaysia in the final round by scores of 21–18, 13–21, 21–10.

In October 2009, he won his first Superseries ever in Denmark Open, after beating Marc Zwiebler of Germany in the final round, 21–14, 21–6.

In June 2012, he won Indonesia Open Superseries Premier title 21–18, 13–21, 21–11 after defeating Du Pengyu of China in the final.

[7] Born in Tegal, Central Java, Santoso is the youngest of four children of Hosea Liem (father) and Rahel Yanti (mother).