Yoshihiro Akiyama is a decorated judoka who moved to mixed martial arts where he became the 2006 K-1 HERO'S Light Heavyweight tournament champion. A fourth-generation ethnic Korean born in Japan, he obtained Japanese nationality as an adult.

Akiyama's mixed martial arts debut was in the K-1 Premium 2004 Dynamite event on December 31, 2004, where he defeated boxer Francois Botha by armbar submission in the first round. His only defeat has been to Jerome LeBanner, who knocked him out with knees in his second fight at the K-1 HERO'S 1 event on March 26, 2005. He has notable wins against Tokimitsu Ishizawa, Taiei Kin, Kestutis Smirnovas and Melvin Manhoef. Akiyama defeated Melvin Manhoef was the K-1 Hero's light-heavyweight Grand Prix 2006 final, and he gained the champion belt.

In K-1 Premium 2006 Dynamite, Akiyama fought Kazushi Sakuraba in the main event. During the match, Sakuraba called to the referee saying "[Akiayama is] Slippery!" Akiayama went to win the match with a referee stoppage. This created a controversy amongst MMA fans in Japan, assuming Akiyama was using some sort of body oil or lubricant, banned in K-1 rules.

But at this moment, Akiyama answered to questions about the oil in the interview as follows: "I have no idea why Sakuraba felt slippery. It may be my sweat, as I sweat a lot always and it often drips off my body."

On January 11, Akiyama and FEG (the parent company of K-1) held a press conference during which Akiyama said he used Olay lotion prior to the fight. Pre-fight footage also showed Akiyama casually applying lotion to his body in his locker room. As a result, Akiyama was disqualified and his prize money was suspended. Akiyama himself was suspended indefinitely from HERO'S competition six days later. Public outcry against Akiyama did not cease however, and Nike was swamped with complaints when Akiyama was featured on a television commercial in Japan. Though Akiyama has admitted to applying cream to his skin, he has said that the purpose was not to gain an unfair advantage but to treat his dry skin. The fight was ruled a "No Contest".

Akiyama was cleared from his FEG-induced suspension and FEG announced that Akiyama would return to K-1 Hero's in Seoul, on October 28, 2007. His opponent was Denis Kang, who was the finalist of PRIDE Bushido Grand Prix 2006 and making his debut in HERO'S. Though he was expected as an underdog, Akiyama beat Kang by KO in the first round.

On December 31, 2007, Akiyama faced Kazuo Misaki at Yarennoka!. The rules of the match stated that kicks to the head of a downed opponent would not be allowed. Late in the first round Misaki knocked down Akiyama with left hook, and as Akiyama struggled to his feet, Misaki delivered a lunging kick to the face which knocked Akiyama out.

The match was ruled a knockout victory for Misaki, but Akiyama contended that one or more of his hands were on the mat at the time of the kick, which would make the kick a foul under the Yarennoka! rules. After reviewing video of the knockout, the Yarennoka! executive committee agreed; the official result was changed to a no contest.