The movie is based on the story of the actor's early years, during which he accompanied his glamorous mother, Anne Hamilton Spalding, on an extended road trip across the country to track down a father for her boys.
Chris Noth, Steven Weber and Nick Stahl are among the suitors, while Mark Rendall is George's brother.
Shooting begins June 9 in the Baltimore area.
Lerman, represented by Endeavor and Lisa Lerman, is best known for his work in 3:10 to Yuma. He also starred in Jack and Bobby.