Champion, 52, will be managing editor and the on-air face of the Weather Channel.
"While he is leaving ABC News, he will always be a part of our family," Sherwood said.
Champion began his career with WABC-TV in New York in 1988 and joined the "Good Morning America" team in 2006.
Since then, he has broadcast more than 1,800 weather forecasts, and has traveled to nearly every major weather event, nationally. His reporting on Superstorm Sandy in 2012 contributed to ABC's Peabody Award for coverage of that historic storm.
For information, visit the abc.com website.