Niinimäki began training in kickboxing at the age of 15, and mixed martial arts at 19.[3][4] He made his professional MMA debut in October 2002 in his native Finland. He assembled an impressive record of 9-2 in the first two years of competition, with all but one of his wins coming by way of submission or TKO.
Beginning in 2005, Niinimäki hit a rough patch where he lost three fights in a row. After one more win in 2007, he retired from competition,[4] saying that he had "lost his fire" to compete.
After a two and a half year hiatus, Niinimäki returned to the sport in February 2010. Since his return he has been unbeaten and maintained an 11-fight winning streak[5] before signing with the Ultimate Fighting Championship.
Niinimäki was expected to face Thiago Tavares on May 31, 2014 at UFC Fight Night 41.[7] However, on May 14, Tavares pulled out of the fight due to thigh injury and was replaced by Niklas Bäckström.[8] Niinimäki lost the back-and-forth fight in the first round by submission.
Niinimäki next faced Chas Skelly on August 23, 2014 at UFC Fight Night 49.[9] He lost the fight via submission in the first round.
On November 7, 2014 Niinimäki announced that he had signed a new four-fight contract with UFC.[10]
Niinimäki was expected to face Rony Jason on December 20, 2014 at UFC Fight Night 58.[11] However, Jason pulled out of the bout on December 10 and was replaced by promotional newcomer Renato Moicano.[12] Niinimäki lost the bout via submission in the second round.
On January 27, 2015, MMAFighting.com reported that Niinimäki had been released from his UFC contract along with four other fighters.[13]
Post-UFC career
In late April 2016, Niinimäki was announced as one of the fighters that had signed on with new European promotion European Fighting Challenge.[14]
Personal life
Before moving to Boca Raton, Florida, Niinimäki lived his entire life in Turku, Finland and worked as a bouncer in several nightclubs.[15]
Management and sponsors
In the early 2012, Niinimäki signed a two-year management contract with Authentic Sports Management. After closing the deal, the management rapidly sent Niinimäki to train at Imperial Athletics gym with a mixed martial arts group later known as Blackzilians.[16] In January 2014, Niinimäki moved to Florida to be able to continue training with Blackzilians at Jaco Hybrid Training Center.[15]
In May 2014, online gambling company Unibet announced a sponsor deal with Niinimäki.[17]