In 1978, a very nervous 23-year-old Steve Jobs (sporting some magnificent facial hair) was interviewed on KGO-TV San Francisco. Though footage of the interview itself has (probably) been lost, the prep from 30 minutes before still exists. This is billed as Steve's first TV appearance, and it certainly seems that's true.
Note his surprise at learning he'll be broadcast in New York, and the best takeaway line ever: "I'm deathly ill, actually, and ready to throw up at any moment."
Given the date, it's unlikely he's announcing a product (the Apple II Plus wouldn't be released until 1979), so this interview was probably promotional for the original Apple II, which launched the previous year.