There were other clubs interested in the 25-year-old former Gillingham defender but he has turned them down to come to Hull and compete with Andy Dawson for a place.
30-year-old midfielder Lewis, who had a 13-game loan spell with City at the back end of last season, is undergoing a medical and if all goes well he will also sign a one-year deal.
Peter Taylor has been after Lewis since he was released by Leicester in May, and is now set to get his man.
City's other summer signings Leon Cort, Michael Keane, Delroy Facey and Sergio Leite have joined up with their new teammates for pre-season training. One more signing, a striker, is expected.