Gilliam is best known for winning the individual NCAA Division I Men's Golf Championship in 2001.

[1] He attended Preble High School in Green Bay until halfway through his junior year, when he moved to Gainesville, Florida to complete his final year and a half of high school.

Gilliam was recognized as a Florida Academic Scholar and graduated from Gainesville High School.

[3][4] Gilliam shot a final-round score of 71 to win the individual NCAA championship with a 72-hole total of 276 (-12).

[3][4] He was also a three-time All-Southeastern Conference (SEC) academic selection (1999, 2000, 2001),[3] and was recognized as an All-American in 2001.