 In is the eldest of two siblings and his younger brother, In Doo-jin, is also an actor.In married actress So Yi-hyun on October 4, 2014.In and So had been friends for a decade before dating; they were costars in "Fairy and Swindler" (2003), "Aeja's Older Sister, Minja" (2008) and "Happy Ending" (2012).