|Born||March 10, 1976|
Toronto, Ontario, Canada
|Height||6 ft 0 in (1.83 m)|
|Weight||170 lb (77 kg; 12 st)|
|Reach||76 in (193 cm)|
|Fighting out of||Toronto, Ontario, Canada|
|Team||Grant Brothers MMA / Tapstar / Bruckmann Martial Arts|
|Rank||Black belt in Brazilian Jiu-Jitsu|
|Mixed martial arts record|
|Mixed martial arts record from Sherdog|
Pierson began wrestling in the fourth grade and competed all the way through college, attending Brock University, and was a member of the Canadian National Team for the Greco-Roman and Freestyle categories. Pierson's other accomplishments in the sport include winning multiple national championships in the Greco-Roman category and a Canadian university national freestyle championship. Pierson also trained in judo during high school.
Mixed martial arts career
Bellator Fighting Championships
Pierson was set to compete in Bellator's Second Season Welterweight Tournament but an injury forced him out of the tournament. He was set to have his first fight against Dan Hornbuckle which would have taken place at Bellator 15.
Ultimate Fighting Championship
After TJ Waldburger had to pull out of his fight with Matthew Riddle at UFC 124 due to injury, it was announced on October 27 that Pierson had signed with the UFC to step in on short notice. After outstriking Riddle over three fast-paced rounds, Pierson won a unanimous decision (30–27, 30–27, 30–27). The fight was dubbed by Dana White as the real Fight of the Night.
Pierson was expected to face Brian Foster on April 30, 2011 at UFC 129. However, Foster was forced out of the bout with an injury, and replaced by Jake Ellenberger. Pierson lost to Ellenberger via first-round KO after he was caught by a counter left.
Pierson was expected to face Dan Miller on September 22, 2012 at UFC 152. However, Miller pulled out of the bout after getting news about his son's kidney transplant operation  and was replaced by Lance Benoist. Pierson defeated Benoist via unanimous decision.
Pierson was expected to face TJ Waldburger on June 15, 2013 at UFC 161. However, Waldburger was pulled from the event and replaced by Kenny Robertson. Despite being hurt in the third round, Pierson won the fight by majority decision.
Pierson lives in the town of Whitchurch-Stouffville, is married and has two sons. Pierson has at least temporarily left his job at the Toronto police force since they would not allow him to have a secondary source of income (as a UFC fighter) while being employed by the Toronto Police force. The police force was against Pierson's participation in these events because of the nickname 'Pimp Daddy' he had back in his early twenties.
Pierson is a top video game player having won tournaments and finishing third in a Canada Wonderland tournament.
Mixed martial arts record
|Professional record breakdown|
|20 matches||14 wins||6 losses|
|Win||14–6||Kenny Robertson||Decision (majority)||UFC 161||June 15, 2013||3||5:00||Winnipeg, Manitoba, Canada|
|Win||13–6||Lance Benoist||Decision (unanimous)||UFC 152||September 22, 2012||3||5:00||Toronto, Ontario, Canada|
|Win||12–6||Jake Hecht||Decision (unanimous)||UFC on FX: Johnson vs. McCall||June 8, 2012||3||5:00||Sunrise, Florida, United States|
|Loss||11–6||Dong Hyun Kim||Decision (unanimous)||UFC 141||December 30, 2011||3||5:00||Las Vegas, Nevada, United States|
|Loss||11–5||Jake Ellenberger||KO (punches)||UFC 129||April 30, 2011||1||2:42||Toronto, Ontario, Canada|
|Win||11–4||Matthew Riddle||Decision (unanimous)||UFC 124||December 11, 2010||3||5:00||Montreal, Quebec, Canada|
|Win||10–4||Ricky Goodall||TKO (punches)||W-1 New Ground||October 23, 2010||1||1:44||Halifax, Nova Scotia, Canada|
|Win||9–4||Fabio Holanda||KO (punches)||Wreck MMA: Fight for the Troops||December 12, 2009||1||1:41||Gatineau, Quebec, Canada||Catchweight (173 lbs) bout.|
|Win||8–4||Jason Rorison||TKO (punches and knees to the body)||Ringside MMA: Rage Fighting||August 22, 2009||1||3:57||Montreal, Quebec, Canada|
|Win||7–4||Iraj Hadin||TKO (punches)||W-1 MMA 2: Unplugged||June 13, 2009||1||2:55||Gatineau, Quebec, Canada|
|Win||6–4||Jacob MacDonald||Submission (punches)||TKO 35: Quenneville vs Hioki||October 3, 2008||1||1:45||Montreal, Quebec, Canada|
|Loss||5–4||Jesse Bongfeldt||TKO (punches)||HCF: Unfinished Business||July 21, 2007||2||4:41||Alberta, Canada|
|Win||5–3||Chester Post||TKO (punches)||TKO: MMA 2007 Tourney||March 17, 2007||1||1:52||Victoriaville, Quebec, Canada|
|Loss||4–3||Steve Vigneault||Decision (unanimous)||TKO 13: Ultimate Rush||September 6, 2003||3||5:00||Montreal, Quebec, Canada|
|Win||4–2||Mark Colangelo||Submission (armbar)||UCC 10: Battle for the Belts 2002||June 15, 2002||1||4:19||Gatineau, Quebec, Canada|
|Loss||3–2||John Alessio||KO (head kick)||UCC 7: Bad Boyz||January 25, 2002||2||1:14||Montreal, Quebec, Canada|
|Win||3–1||Ali Nestor Charles||Submission (heel hook)||UCC 3: Battle for the Belts||January 27, 2001||1||2:09||Sherbrooke, Quebec, Canada|
|Loss||2–1||Chad Saunders||Submission (heel hook)||IFC: Warriors Challenge 8||June 14, 2000||1||1:11||Friant, California, United States|
|Win||2–0||Steve Vigneault||TKO (punches)||IFC: Battleground 2000||January 22, 2000||1||1:17||Kahnawake, Quebec, Canada||Welterweight debut.|
|Win||1–0||Steve Vigneault||TKO (punches)||IFC: Montreal Cage Combat||October 9, 1999||1||1:07||Montreal, Quebec, Canada|
- http://boxing.nv.gov/2011%20Results%20Web/12-30-11%20MMA.pdf[permanent dead link]
- "Bellator welterweight tourney kicks off at Bellator 14 and Bellator 15, matchups set". Archived from the original on 2010-02-28. Retrieved 2010-02-26.
- Steven Marrocco. "Sean Pierson replaces injured T.J. Waldburger, meets Matt Riddle at UFC 124". MMAjunkie. Archived from the original on 2012-07-14.
- "Brian Foster vs. Sean Pierson in the works for UFC 129 in Toronto". MMAJUNKIE.com. 2011-01-07. Archived from the original on 2011-01-12. Retrieved 2011-01-21.
- "Brian Foster Out of UFC 129 After Pre-Fight Medical Reveals Brain Hemorrhage". mmaweekly.com. April 12, 2011.
- "Ellenberger in for Foster, faces Pierson at UFC 129". ufc.com. April 13, 2011.
- Rice, Joe (October 3, 2011). "Dong Hyun Kim vs. Sean Pierson scheduled for UFC 141". mmatraining.com. Retrieved October 3, 2011.
- "Sean Pierson vs. Jake Hecht added to UFC on FX 3 in Florida". mmajunkie.com. 2012-04-06. Archived from the original on 2012-04-09.
- "UFC 152 adds Miller vs. Pierson to Toronto show". mmajunkie.com. August 2, 2012. Archived from the original on August 4, 2012.
- Pishna, Ken (August 24, 2012). "Dan Miller Happily Steps Off UFC 152 Fight Card for His Son". mmaweekly.com.
- "With Miller out, Sean Pierson now meets Lance Benoist at UFC 152 in Toronto". mmajunkie.com. August 24, 2012. Archived from the original on January 3, 2013.
- "Sean Pierson vs. Rick Story added to UFC 158 in Montreal". MMAjunkie.com. January 8, 2013.
- Sousa, Jonas (2013-02-05). "Pierson out; Quinn Mulhern faces Rick Story at UFC 158". imperiomma.com. Archived from the original on 2013-06-18. Retrieved 2013-02-05.
- Karim Zidan (2013-03-06). "Sean Pierson vs. TJ Waldburger Added To UFC 161 In June". theflyingkneemma.com. Retrieved 2013-03-06.
- Staff (2013-05-02). "TJ Waldburger Out, UFC 161 Match-up Now Pits Sean Pierson vs. Kenny Robertson". MMAweekly.com. Retrieved 2013-05-02.
- "Toronto native Pierson achieves UFC dream". Sportsnet.ca. 2010-12-09. Archived from the original on 2010-12-15. Retrieved 2010-12-16.
- "Police force dumps UFC fighter "Pimp Daddy"". thestar.ca. 2010-12-15. Retrieved 2011-01-08.
- Toronto News: What did UFC fighters have to say about bullying?. thestar.com (2011-12-06). Retrieved on 2011-12-14.
- "Top MMA News Catches Up With Sean Pierson". TopMMANews.com. 2012-12-03. Retrieved 2012-12-03.