Growing up, Simien was a KU fan due to his proximity to Lawrence. He committed to play for Roy Williams and Kansas as early as the 8th or 9th grade, and was later named to the 2001 McDonalds All American team.
At the University of Kansas, Simien received All-American honors his junior and senior years. He was a Wooden Award finalist both years, and was the Big 12 Player of the Year his senior year. However, his college career ended on a sour note when Kansas was defeated by 14th-seeded Bucknell in the first round of the 2005 NCAA Tournament. Simien finished his college career with 110 wins and a 12-4 NCAA Tournament record.
He was selected with the 29th overall selection of the 2005 NBA Draft by the Miami Heat.
It has been reported that Simien will be getting married in July of 2006.