In football, he played quarterback, linebacker and safety, and as a senior, he was named the Bay League's Defensive Player of the Year and was an All-California Interscholastic Federation selection.
Ellison went on to start 7 games for the Bills in 2006, filling in for both Takeo Spikes and Angelo Crowell because of injuries they suffered throughout the year.
Ellison recorded 65 total tackles (33 solo), 1 sack, 1 interception, and 1 fumble recovery in 2006, his rookie campaign.
A restricted free agent in the 2009 offseason, Ellison signed a one-year, $1.01 million contract with the Bills on March 25.
The Buffalo Bills announced March 4, 2010 that it has tendered a contract offer to restricted free agent linebacker Keith Ellison, a sixth-round pick in 2006.