Reynolds was quickly erased from the show's opening credits, now down to three women from the usual five.
"It is becoming uncomfortable for us to pretend that everything is the same at this table," said show creator Walters. "Therefore, regrettably, Star will no longer be on this program."
ABC had decided against renewing Reynolds' contract months ago and the show was planning to let Reynolds announce it later this week, according to Walters. Reynolds could say whatever she wanted to about why she was leaving, "and we would back her up," the longtime ABC newswoman said.
Instead, Walters said she felt blindsided when Reynolds broke the news Tuesday, then was quoted in People magazine as saying she felt like she was fired.
"We gave her time to look for another job and hoped that she would announce it on this program and leave with dignity," Walters said. "But Star made another choice."
Reynolds' spokesman did not return calls and e-mails seeking comment.
Walters didn't discuss on the air why Reynolds, an original cast member who's been on the show for nine years, wasn't being asked back. She said in an interview Tuesday that research showed audience members were turned off by Reynolds' dramatic weight loss and glitzy wedding to banker Al Reynolds in 2004.
Reynolds later retorted that TV ratings and her book sales indicated this wasn't true.
"The View" is bringing on Rosie O'Donnell to replace Meredith Vieira in September, and the hunt is now on for Reynolds' replacement. Walters said Reynolds may still appear on the show in recorded segments.