On Sunday night he was in Hollywood, as co-host of the Oscar telecast in black tie. At 9 the next morning, he was in a Starbucks in New Haven, hunched over a book and barely recognizable in a gray sweatshirt, but still wearing his tuxedo pants.

James Franco, movie star, had rushed back on the red-eye to play his other big role: Yale doctoral student. By 9:25, he was at his seat in a seminar on medieval manuscripts. “I was surprised and delighted that he made it to class,” said Jessica Brantley, an associate professor of English. “He’s a dedicated student.”

Mr. Franco seemed to shrug off the bad reviews of what many in the national news media called an inert performance at the Academy Awards show. Yet later on Monday, he pounced on The Yale Daily News for some mild criticism of his monosyllabic Twitter style, posting a message with an obscenity scrawled in red Photoshop paint.