Sessel, formerly vice president of global engineering, and Carney, former senior vice president of procurement and information technology at IAC, will report to COO Brian Pour -- who was also promoted earlier this week.
IAC is incorporated in Luxembourg, but its operational headquarters is in suburban Detroit.
"This new leadership structure is intended to better align with IAC's strategic direction," said IAC CEO Steve Miller. "Maurice has invaluable knowledge of the North American automotive industry that will drive IAC's business strategy in the region."
Prior to joining IAC in 2007, Sessel and Carney served in several vice president roles at Lear Corp. IAC was formed in 2006 from the European assets of Collins & Aikman and the North American interiors unit of Lear.