Following his collegiate career, Frost was selected in the third round (67th overall) of the 1998 NFL Draft by the New York Jets as a safety. As a rookie in 1998, Frost played in 13 games mostly on special teams, making six tackles and two passes defended. In 1999, Frost played in 14 games with seven tackles. Playing in all 16 games in 2000, Frost made his first career start against the Buffalo Bills on October 29. Frost also got his first career interception against Bills quarterback Rob Johnson on September 17 and first career sack against the Oakland Raiders' Rich Gannon on December 11.