jonathan jacob walker (born september 17, 1985 in chicago) is an american musician. he was the bassist for the las vegas based rock band panic at the disco, replacing former bass player brent wilson. he was replaced by dallon weekes after he left the band in july, 2009. jon walker was also lead guitarist and occasional lead vocalist of the young veins. as of 2011 he is trying a solo career as a folk-pop artist.