He announced the news Tuesday morning in the show's Times Square studio.
"I'm curious, when I'm here a few days a week, does that play every time?," Strahan, 42, joked of the 30-second clip reel showing him as a baby, Super Bowl-winning NFL star and TV personality that preceded his arrival.
The former New York Giants football player says his new gig will not get in the way of his daily duties on "LIVE! With Kelly & Michael." He previously called his hosting duties alongside Kelly Ripa his "home."
Strahan also works for Fox Sports during the football season. He cited that as main reason why "he wouldn't do it every day."
In light of his busy schedule, the "GMA" crew presented him with an alarm clock and a giant coffee cup.
"I appreciate it because you can never have enough alarm clocks," said Strahan.
Before leaving for "LIVE! With Kelly & Michael," Strahan announced the show's next guests, "Dancing With The Stars" cast-offs Cody Simpson and Witney Carson. The duo then surprised Strahan by wheeling in a wheelbarrow full of Sour Patch Kids.
"Sugar and coffee in the morning," Strahan said, holding a candy bag with his "GMA" mug. "Good morning, America!"
He will return to the ABC breakfast show "next week."
"GMA" recently lost Sam Champion to The Weather Channel and Josh Elliot to NBC Sports, leaving George Stephanopoulos with four women: Robin Roberts, Amy Robach, Lara Spencer and Ginger Zee.
ABC News and The Associated Press contributed to this report.