Williams was born and raised in suburban Pittsburgh and Detroit, Michigan. She attended the University of Miami. Williams is a silver medalist in the 100 meters at the 2004 Summer Olympics and a 4-time medalist at the World Championships in Athletics, where she won (together with Angela Daigle, Muna Lee and Me'Lisa Barber) a gold medal in the 4x100 m relay in 2005 and 2007, as well as gold and silver in the 100m in 2005 and 2007 editions of the meet.
In the Beijing Olympics of 2008, Williams ran the anchor leg in the relay, but a mix-up in the semi-final with team-mate Torri Edwards caused Edwards to drop the baton. Williams picked up the baton to finish in last place, but the USA was disqualified because she had had to run outside her lane in order to retrieve the baton. At the individual 100 metres sprint she placed 2nd in her first round heat behind Christine Arron in a time of 11.38 to advance to the second round. There she improved her time to 11.07 seconds and placed 2nd again, this time behind Kerron Stewart. With the third time in her semi final heat behind Shelly-Ann Fraser and Muna Lee she qualified for the final in 11.10 seconds. In the final she came to 11.03, finishing in fourth place, just outside the medals that all went to Jamaica.
|2002||World Junior Championships||Kingston, Jamaica||100m||1st||11.33 secs|
|2004||Olympic Games||Athens, Greece||100m||2nd||10.96 secs|
|World Athletics Final||Monaco, Monaco||100m||3rd||11.21 secs|
|2005||World Championships||Helsinki, Finland||100m||1st||10.93 secs|
|World Athletics Final||Monaco, Monaco||100m||3rd||11.04 secs|
|2006||World Indoor Championships||Moscow, Russia||60m||2nd||7.01 secs|
|2007||World Championships||Osaka, Japan||100m||2nd||11.01 secs|