Samsung Electronics Co. spent an estimated $20 million on ads to run during breaks in the Academy Awards broadcast on Sunday night. But Samsung may have got more promotional mileage from Oscars host Ellen DeGeneres during the show itself.

Ms. DeGeneres toyed with a white Samsung phone during the broadcast, including when she handed a Galaxy Note 3 to actor Bradley Cooper so he could take a "selfie" photo of himself and other stars including Brad Pitt, Meryl Streep, Kevin Spacey and Jennifer Lawrence surrounding...