He entered Dong-A University on a taekwondo scholarship in 1995 and performed consistently well in national competitions during his college years, though usually overshadowed by the dominant heavyweight championKim Je-Gyoung. Upon graduation from Dong-A University in Busan, South Korea in 1999, Moon became a member of the Samsung Corporation Professional Taekwondo team. Many considered Moon to be the next Kim Je-Gyoung, two time Olympic Gold Medalist and also a member of the Samsung Professional Team and graduate of Dong-A University, in the heavyweight division of the Korean National team. Since his high profile win at the Athens Olympic Games, Moon has become a well known celebrity in South Korea, owing to his performance in the Gold Medal round. He has become the official Audi Automobile Company's spokesman and has made numerous television and public appearances. Notable abilities which make him an elite and consistent athlete are: Left leg roundhouse kick, left leg back kick and reverse as well as a solid grasp of other core techniques indispensable to fighting in high level international and Korean domestic competitions.
His doctoral thesis for Kookmin University, "Effect of Proprioceptive Neuromuscular Facilitation on Flexibility and Isokinetic Muscle Strength in Taekwondo Player", came to the attention of the public media in South Korea as a "copy-and-paste" plagiarism. There are a number of "copy-and-paste" paragraphs in introduction, literature review, and discussion section of the thesis. The scandal later affected his rookie political career, but he decided to stay in the ruling party and maintained his innocence. In April 2012, the research ethics committee of the Kookmin University announced: "The research subject of the doctoral thesis by Moon Dae-sung and part of the purpose of the research of his thesis overlap with those of a doctoral thesis by a person surnamed Kim at Myongji University. Not only that but a significant portion of the writing in the introduction, the theoretical background and the arguments in the two theses are so identical that we concluded this goes beyond what is normally permitted by the academic community." Minutes after the school’s announcement, Moon issued a statement to announce his departure from the ruling party. In March 2014, Kookmin University officially canceled his PhD. Moon launched a nullification lawsuit, which his opponents believe is a tactic to keep his seat in the IOC as well as the ruling Saenuri Party.
