Todd, 51, told viewers that “I’ve watched too many friends and family let work consume them before it was too late” and that he’d promised his family he wouldn’t do that.
Todd has often been an online punching bag for critics during a polarized time, and there were rumors that his time at the show would be short when its executive producer was reassigned at the end of last summer.
It’s unclear when Todd’s last show will be, but he told viewers that this would be his final summer.
“I leave feeling concerned about this moment in history,” Todd said.
Welker, a former chief White House correspondent, has been at NBC News in Washington since 2011 and has been Todd’s chief fill-in for the past three years.
Rebecca Blumenstein, NBC News president of editorial, praised her new host’s talents in a memo announcing Welker’s elevation on Sunday.
Now Welker, 46, will be thrust into what promises to be another contentious presidential election cycle.
Adapted from reporting by the Associated Press