Kellum has perviously served as the Chief Deputy Executive Director at California Infrastructure and Economic Development Bank since 2021. He held multiple positions at the Department of Finance from 2011 to 2021 including Assistant Program Budget Manager from 2017 to 2021 and Principal Program Budget Analyst II/III from 2013 to 2017. Kellum held multiple positions with the California Department of Corrections and Rehabilitation from 2008 to 2011, including Staff Services Manager I in 2011 and Associate Budget Analyst and Staff Services Analyst from 2008 to 2010. He was a Financial Advisor at Morgan Stanley from 2006 to 2007. Kellum earned his Bachelor of Science degree in Finance from California State University, Sacramento.