Mr Davis was a major Conservative Party defector when he made the call during Prime Minister's Questions (PMQs) in January.
It was particularly damaging for Mr Johnson as Mr Davis is well-respected among Tory backbenchers, and is a former Brexit Secretary.
This week, speaking as Mr Johnson faces yet more pressure to step aside after the release of the much-anticipated Sue Gray report, the 73-year-old spoke to GB News' Gloria de Piero.
Gloria asked the former Tory leadership candidate: "So, earlier this year, since we’re onto Boris Johnson, it was one of those breathtaking moments in PMQs when you said to the Prime Minister: ‘In the name of God, go.’ Was that a mistake?"
David Davis speaking to GB News
GB News
GB News' Gloria de Piero
GB News
Speaking in Gloria's Life and Times series, Mr Davis replied: "No, not at all.
"When I change my mind, I’ll let you know. I’ll come on your programme and tell you!"
Mr Davis, who with Mr Johnson was instrumental in the downfall of former Prime Minister Theresa May when he rejected her Chequers plan in 2018, then discussed his morning routine.
He added that Mr Johnson's move to deflect blame onto his staff was what triggered his Partygate anger.
Mr Davis told Gloria: "What happened that morning, and I decided that morning. I was on my exercise bike.
"My morning starts with ten minutes on the exercise bike, ten minutes on the rowing machine.
"And I watch the night before’s news because I don’t get home, often, until after the news, so I always record it.
"And I watched the Beth Rigby interview when he appeared to blame his subordinates. All this ‘they didn’t tell me,’ all that sort of stuff.
"Now, I was brought up in business and in military, in politics I was a minister: you don’t blame your subordinates. You shoulder the responsibility.
"I mean, you used that phrase in the intervention, that you shoulder the responsibility for your own actions.
"And that was the point at which I thought it had just gone too far. I’d been defending him up until then.
"I thought, you know, if he doesn’t go we’ll have – in fact, I actually gave an interview – we’ll have death by 1,000 cuts, the blame will spread to other Cabinet ministers, then it will spread to the rest of Government, then it will spread to the rest of the party, and it will go on until Christmas.
"Well, so far, every single one of my predictions has been right."
David Davis said he had no regrets
GB News
Gloria de Piero dubbed it a 'breathtaking' moment in PMQs
GB News
Mr Davis, who worked in business and served in the military before going into politics, then moved to clarify his intervention.
He continued: "The bit that people forget about that quote was the first bit, because it was a quote from Cromwell originally; it was actually a quote of a quote from Cromwell, taken by one of Churchill’s supporters from Cromwell.
"And the first bit is: ‘You have sat there too long for all the good you have done.’
"I wasn’t denying he’d done a lot of good. He’d delivered Brexit and all these things and got us through Covid. I’d had my disputes about that, but never mind.
"And it was ‘you’ve sat there too long for all the good you’ve done.’ You’ve done so much good – don’t blight it. And that was my basic line, and that was it, that was the reason.
"I don’t regret it. I had 1,000 enemies the next day. Well, later that day.
"But, since then, I’ve had a million supporters.
"It’s quite plain that no ordinary person, I mean, outside Boris’ circle – of course they’re cross with me, they’d be wrong not to be – but on the doorstep, on the train, in the streets, in the tearoom, everywhere, people say: ‘Actually, you were right.’"
