Onobun began his college career playing basketball at The University of Arizona in 2006. He was recruited by Lute Olson.
Onobun played four years of basketball at the University of Arizona. He joined the Houston Cougars football team in 2009 and played an important role on special teams. He appeared in 11 games and hauled in a 15-yard catch against SMU for the first reception of his career. Onobun blocked two extra points against C-USA rival Southern Miss and caught an 18-yard touchdown against Memphis.
Onobun signed a four-year $1.92 million deal with a signing bonus of $129,000. Onobun, considered a risky pick, made the St. Louis Rams opening day roster in 2010. He was waived during final cuts on September 3, 2011.
The Buffalo Bills signed Onobun on December 9, 2011. He was cut on August 26, 2012.
Chicago Bears
On January 10, 2013, the Chicago Bears signed Onobun.[4] Onobun was cut on August 30, 2013.[5] On September 1, Onobun was signed to the Bears practice squad.[6] Onobun was cut on June 19, 2014.[7]
Jacksonville Jaguars (second stint)
Onobun was signed by the Jaguars on August 7, 2014. He was waived/injured on August 20 and spent the season on injured reserve. He became a free agent after the 2014 season.