[1][2] Harrison holds notable wins over: Muangthai P.K.Saenchai, Tetsuya Yamato, Malaipet Sasiprapa, Mehdi Zatout, Andrei Kulebin, Anuwat Kaewsamrit, and Dzhabar Askerov.

Brought up in Leeds, Harrison first started training in Muay Thai aged 13, when he joined the Bad Company gym in Harehills.

Despite the late change of opponent and fighting in a rule set different from Muay Thai, Harrison won the match by technical knockout to become world champion.

The win in Italy was followed by success at home when Harrison defeated Dutch-based kickboxer Mohamed Ajuou to claim the European version of the S.I.M.T.A.

He made his Thai debut in August of that year, losing a split decision to Witthayanoi Sitkuanem at Rajadamnern Stadium in what was the first defeat of his pro career.

Harrison suffered a second consecutive loss a few months later on his return to England, losing to another Thai in Duwao Kongudom who was a highly rated Omnoi Stadium champion, in a match in Wolverhampton.

He won his first title on Thai soil by defeating a much bigger Russian opponent to claim the Patong Stadium belt at 68 kg (149.6 lbs).

Liam lost the first match between the pair, but won the second in Manchester in November via a fourth-round KO, picking up his biggest victory up to that point as well as winning the W.M.C.

[5] In 2008 Harrison fought a number of bouts at Bad Company promoted shows in his home town of Leeds, with wins over Benabdeljelil Mehdi and Masaru Ito.

[citation needed] Harrison would gain revenge against Anuwat Kaewsamrit in March 2010, defeating him by unanimous decision over five rounds in their rematch in Manchester.

Harrison lost to Saenchai PKSaenchaimuaythaigym for the third time at Muay Thai Warriors in Macau on 9 December 2012, losing a clear-cut unanimous decision.

[10][11][12] He lost to Sagetdao Petpayathai by decision in the semi-finals of a four-man 68 kg tournament at MAX Muay Thai 3 in Zhengzhou, China on 10 August 2013.

[13][14][15][16] Harrison stopped his four-fight losing streak with a unanimous decision victory over Dylan Salvador at The Main Event 2013 in Manchester, England on 2 November 2013.

[29] Harrison faced Nong-O Gaiyanghadao for the ONE Bantamweight Muay Thai World Championship at ONE on Prime Video 1 on 27 August 2022.

[33] Harrison was scheduled to fight former unified multiple division champion Floyd Mayweather Jr. in an exhibition bout, but pulled out.