“Once Upon a Time” creators Adam Horowitz and Eddy Kitsis had high expectations while casting the new ABC skein. “One of our emotional centers was an 11-year-old boy who had to be precocious and vulnerable at the same time,” the showrunners say.

Then they met Jared Gilmore. The 11-year-old actor “naturally brought that out,” Katsis explains. “We just knew he had to be our Henry!”

Gilmore fell into acting after a chance encounter with agents initially looking to rep his twin sister, Taylor Gilmore. Though his sis later decided to ditch the biz, Jared stuck with acting, landing spots in commercials and, eventually, TV and film.

The California native’s most coveted part has been playing Don Draper’s son Bobby on “Mad Men,” though onscreen sibling Kiernan Shipka gets the juicier subplots. With his new role in “Once Upon a Time,” however, Gilmore faces a much bigger challenge.

Kitsis says he enjoys watching Gilmore “try harder and harder to get better,” adding, “With every episode, there’s a growth with him. There is a professionalism, but that little-boy spirit is always there, and that’s what brings so much heart to the role.”