Sumners grew up in Shelby County and graduated from Pelham High School in 1991. He went on to earn a bachelor's degree in political science at the University of Alabama, where he played on the Crimson Tide soccer team. He worked as a recycling coordinator for the Alabama Environmental Council from 1995 to 1996 and completed his schooling in 2001. He and his brother Paul founded the Sumners 2 Photography that year, specializing in commercial stock photography. From 2003 to 2007 he was also a partner with Scott Planson in Changing Spaces Moving.
As a candidate in the 2009 special election to fill the vacancy left by Larry Langford's criminal conviction, Sumners pledged to communicate with neighborhood associations. He also expressed interest in installing photovoltaic panels at city buildings and hosting a constitutional convention to replace the Alabama Constitution of 1901. Sumners finished 11th of 14 candidates, with 31 of the 34,931 votes cast.
- Gordon, Robert K. (December 4, 2009) "Birmingham mayor's race: William Jason Sumners wants city to host constitutional convention." Birmingham News