He joined the Memorial Health Board of Directors in March 2004. He served as treasurer for two years, became vice chair in 2009, was chair of the Board from 2011 through 2013, and assumed the role of chairman again in 2017. Lewis is a member of the board of directors for several local corporate and nonprofit entities, including Savannah Health Mission, Union Mission, Inc., and The Savannah Bank, N.A. He is also past chair of the board of directors for Second Harvest Food Bank of Coastal Georgia and the Board of Deacons of First Baptist Church of Savannah.