Yang began his professional career in South Korea in a tournament. Yang won three successive fights. Yang followed this up with a win at the Super Sambo Festival, again via TKO.
Rise to prominence in Asia
Yang then joined the larger DEEP promotion. Here, Yang won two successive bouts, both via TKO. Yang then joined Sengoku and competed in their Sengoku Fourth Battle event. His opponent was Polish judoka Pawel Nastula. After 2:15 of the second round, Yang was victorious via TKO The fight was slightly controversial due to Yang landing a knee in the clinch that earned him a yellow card. After this, Nastula was noticeably sluggish and would later complain of a groin problem. For "inexplicable reasons" the referee stopped the fight and gave a TKO verdict. Yang then defeated two opponents; one in Japan and one in the Northern Mariana Islands. As was becoming a pattern in his career, Yang won both fights via TKO.
In June 2010, Yang signed with the UFC, joining Chan Sung Jung as the members of Korean Top Team competing in Zuffa organizations. Yang's UFC debut was at UFC 121 against The Ultimate Fighter competitor Chris Camozzi. Yang began the fight with a successful takedown, followed by ground-and-pound. After standing up, Camozzi was able to keep Yang at bay with kicks, before engaging in the clinch. However, Yang's thick neck and shoulders prevented effective attacks. Later, Camozzi was able to effectively time the advance of Yang. In the third, Yang began to swing wildly, to no avail. Camozzi was declared the winner via split decision. Yang next fight was against Rob Kimmons on March 3, 2011 at. Yang won the fight by TKO near the end of the second round, giving him his first UFC win. Yang faced Court McGee on September 17, 2011 in the co-main event at UFC Fight Night 25. The match was a pure back and forth kickboxing match. Yang was able to have some success and connected with some punches that wobbled McGee, in the end it was not enough to get the victory. Yang faced Brad Tavares on May 15, 2012 at. Yang was defeated by Tavares via unanimous decision and was subsequently released from the promotion.
Post-UFC
On June 29, 2013 Yang defeated ROAD FC veteran Jae Young Kim by TKO in the second round at Top FC 1 in South Korea. Yang followed that up with an impressive first round TKO of fellow UFC veteran Dennis Hallman at Top FC 6 on April 5, 2015.
Return to UFC
In late August, it was confirmed that Yang had re-signed with the UFC and will continue competing in the promotion's Middleweight division. He faced Jake Collier at UFC Fight Night 79 on November 28, 2015. He won the fight via TKO in the second round. Yang was expected to face promotional newcomer Ryan Janes on October 15, 2016 at UFC Fight Night 97. However, the promotion announced on October 6 that they had cancelled the event entirely.