Mark S. Elwood is CEO of Elwood Staffing, a Columbus, Ind.-based staffing firm. Elwood oversaw the acquisition of SOS Employment Group, which catapulted the staffing firm to the No. 15 slot on Staffing Industry Analysts’ 2013 list of largest U.S. staffing firms in 2013. Elwood joined the firm in 1985 and became CEO in 2000. The company operates 220 service locations across 31 states and extends into Canada.