Genesis wants to move like a startup. Hyundai gives it the muscle to scale like an auto giant.

Ted Mengiste, chief operating officer of Genesis Motor North America, said the luxury brand operates like a startup within Hyundai, a nearly 80-year-old company. David Dee Delgado/Reuters Genesis began as a Hyundai luxury model before becoming a stand-alone brand in 2015. It now sells sedans,…