Spearmon is a graduate ofFayetteville High School and attended theUniversity of Arkansas, where he competed collegiately for two seasons before turning pro. While at Arkansas, he won the 200 metersNCAA Outdoor title in 2004 and 2005 as well as the NCAA Indoor 200 m title in 2005. In August 2005, he won the silver medal in the 200 m at the2005 World Championships and in August 2007, he won the bronze medal at the2007 World Championships. Spearmon won the 200 m at the USA outdoor athletics championships in 2006 and finished second in 2007. At the2009 World Championships in Berlin he won another bronze. He ran a world best time of 31.88 for the 300 m indoors in February 2006.[2]
His personal best in the 200 m is 19.65 seconds. This time (achieved inDaegu, Korea) made him the third fastest man over the distance at that point.[3] He is currently ranked as the fourteenth fastest 200-meter runner ever. Onlyworld record holderUsain Bolt (19.19),Yohan Blake (19.26),Noah Lyles (19.31),Michael Johnson (19.32),Letsile Tebogo (19.46),Erriyon Knighton (19.49),Walter Dix (19.53),Justin Gatlin (19.57),Kenny Bednarek (19.57), his training partnerTyson Gay (19.58),Andre de Grasse (19.62),Xavier Carter (19.63), andReynier Mena (19.63) have run faster.[4] Despite the fact that he normally runs a "slower" first half of his 200 m races and goes on to pass people down the stretch, his 100 meters personal best is 9.96 s. He set that mark running inShanghai on September 28, 2007, beating 100 m world champion Tyson Gay.
He posted a quick time of 19.98 seconds in the 200 m inKingston, Jamaica in April 2010, finishing behind Usain Bolt.[6] He reached the2010 IAAF Diamond League 200 m final at theWeltklasse Zurich meeting, and (in the absence of points leader Walter Dix) he won the first Diamond Race Trophy with a meeting record of 19.79 seconds.[7] Following the Diamond League win, he ran 19.85 seconds to win at theRieti IAAF Grand Prix.[8]
At the start of the 2012 season, he broke Michael Johnson's 200 m meet record at theDrake Relays with a run of 20.02 seconds.[9] He finished fourth in the200 metres final at the2012 London Olympics. His time of 19.90 seconds was 6/100 of a second outside of a medal placing.
Spearmon finished 21st at the2013 World Championships, running a time of 20.66 seconds in the semi-final .
At a meeting in Edmonton in July, 2014, Spearmon tested positive formethylprednisolone contained in a medicine he was taking without asking for an exemption.USADA accepted the excuse so it was treated as a minor violation. On September 19, 2014, it was announced he would receive a 3-month suspension, backdated to August 27.[10]
He is good friends with fellow sprinterUsain Bolt; they are known for their jokes and good friendship.
On an April 2011 episode ofMythBusters, he worked withAdam Savage andJamie Hyneman to investigate the possibility of a human running on water. In May 2013 he returned to the show to race 30 ft against a race car.
As of August 2024, Spearmon holds four track records for 200 metres including Arlington, Virginia (19.95, March 2012), Carson (19.91, May 2007), Rieti, Italy (19.85, August 2010) and Split, Croatia (19.95, September 2010).