Cornejo grew up in
San Bernardino, California, where he attended
Jurupa Valley High School. Cornejo would go on to play
college baseball for the
Riverside Community College. As a freshman at Riverside Community College in 2001, Connejo had a .368
batting average, a .438
on-base percentage (OBP), and a .492
slugging percentage (SLG), with three home runs. As a sophomore in 2002, he transferred to the
University of Oklahoma, Cornejo batted .325 with a .411 SLG, 17 doubles, and 31 RBIs. As a junior in 2003, he batted .393 with a .509 SLG, 2 home runs, and 49 RBIs. Cornejo was drafted by the
Oakland Athletics in the 13th round of the
2003 Major League Baseball draft. He signed with the Athletics on June 6, 2003, forgoing his senior year of eligibility in college. He would play the next five years in the Athletics organization, never advancing above Triple-A. He was released, and signed with the
Colorado Rockies organization where he would finish out the 2008 season. He announced his retirement in 2009. ==Coaching career==