Gilliam attended Villanova University and earned a Bachelor's degree in Finance & Accounting in 2008. He attained his Master's in Finance & Accounting from The London School of Economics in 2009 and MBA from the Stanford Graduate School of Business in 2014.
Early in his career, Gillman was an Analyst and Manager at American Express. He was a Product Manager at clearXchange before it was rebranded as Zelle. Gillman later became a Faster Payment Task Force Member for the Federal Reserve System. In January 2016, he joined Chain which beings cryptographic ledger technology to financial services as the Head of Customer Success.