It was a steady rise, followed by a fast fall.
"He exemplifies the finest values of public service broadcasting," said Lord Patten, chairman of the BBC Trust.
He stood alongside Entwistle as the director general announced his resignation outside the BBC's headquarters in London.
"He's behaved as editor with huge honor and courage," said Patten.
"George was set on putting in place a number of reforms and changes, which will be required in this great organization. It's a real tragedy that he was overwhelmed ... by these events before he was able to act in a way, which is clearly necessary."
Entwistle was not pushed out of his position, Patten told BBC's Andrew Marr show on Sunday.
"He went, and very honorably," he said.
Facing increasing criticism over the Newsnight claims, Entwistle spoke to BBC Radio 4's Today program Saturday shortly before he stepped down. He was pressed on what he knew about the false sex abuse allegations.
Entwistle said he did not find out about the report until after it aired, stressing that not every piece of journalism produced by the BBC rises to his level. He also said he was unaware, initially, of a Guardian report that blasted the piece.
Entwistle's comments struck at least one critic as aloof.
"Publishing a gross libel of this seriousness, at a point when the BBC is under so much pressure, and then to find that the editor in chief appears to know almost nothing about it," Hewlett said.
"That's really what did it for George Entwistle."