Williams graduated in 1997 from Caesar Rodney High School in Camden, Delaware, and was drafted by the Pittsburgh Pirates the following year.

On August 18, the Mets recalled Williams from the Norfolk Tides to make a start in place of Pedro Martínez.

Williams held the St. Louis Cardinals to two runs on seven hits and a walk while striking out four over 6.1 innings to pick up the victory in the Mets' 6-2 win.

He was then designated for assignment on July 14 so Oliver Pérez could return to the Mets rotation from the disabled list.

Williams signed to pitch for the Yokohama BayStars of Nippon Professional Baseball for the 2008 season on December 12, 2007.

He appeared in 21 games as a relief pitcher for Washington's Double-A affiliate, the Harrisburg Senators with a record of 1-3 and an earned run average of 3.56, and 19 games for their Triple-A affiliate, the Syracuse Chiefs, with a record of 0-1 and an earned run average of 7.89.