Wittman, who will report to President Jeff Dyke, will oversee expansion of the company's online retailing platform at franchised dealerships and EchoPark standalone used-vehicle stores.
Wittman most recently was vice president of global e-commerce for Hertz Corp. for about two years and before that worked as associate brand director for Proctor & Gamble Co., among other positions with the consumer goods company.
Conrad, who will report to Wittman and work with outside vendors, comes to Sonic from Belk Inc., where he was director of e-commerce digital experience and site operations for the department store chain.
Sonic also named Marti Eulberg, who was instrumental in creating the EchoPark brand, as its first chief creative officer. Eulberg, 56, had been director of the company's brand management since 2012. She will report to Dyke and will work with Wittman, Conrad and Chief Marketing Officer Rachel Richards to align the company's online sales platforms with its "guest experience and brand management standards," according to Sonic.