Iris and Mike Campbell announced their support of Haley during news conferences Monday in Columbia and Greenville.
Gov. Carroll Campbell served two terms with a Democratic-controlled Legislature, starting in 1987. His job-creation achievements include bringing BMW to the state. He died in 2005.
The popular former governor endorsed Gov. Mark Sanford in a 2002 primary runoff. Sanford later removed Campbell's eldest son from an appointed spot on the State Ports Authority.
Carroll Campbell III lost his bid for Congress this year in a crowded primary. Mike Campbell lost his bid for lieutenant governor in a 2006 runoff.