Johnson, prime minister between 2019 and 2022, faced a second day of questioning on Thursday which examined the weeks before the second lockdown in November 2020.
The inquiry has heard evidence from former advisers that Johnson, fearing the effect on the economy, wanted to let the virus spread rather than order another lockdown, and that he once replied "let the bodies pile high".
Asked whether he thought the virus should be allowed to "let rip" and about suggestions that he believed older people had reached their time, Johnson said: "No, no, no, this is all rubbish," Johnson said.
"The implication that you're trying to draw from those conversations is completely wrong," he said.
"My position was that we had to save human life at all ages and that was the objective of the strategy, and by the way, that is what we did."
Coronavirus killed more than 230,000 people in the UK and infected many millions more.
Johnson resigned after a series of scandals including reports that he, and other officials, engaged in alcohol-fuelled gatherings in Downing Street in 2020 and 2021, when most Britons had to stay at home.
The inquiry has heard damaging testimony about a toxic culture in Downing Street during the pandemic, Johnson's reluctance to lock down and how he was confused by the science of the virus.
Johnson dismissed previous evidence as "accounts... culled from people's jottings" and said the UK went into a second lockdown as soon as the disease picked up again.
In autumn 2020, he said the phrase "let it rip" was in common parlance.
His job, he said, was to challenge the consensus in meetings and ask questions of scientists recommending a full lockdown instead of a policy of shielding vulnerable people and allowing the virus to "rip" among the rest of the population.
"It does not do justice to what we did, our thoughts, our feelings, my thoughts, my feelings, to say that we were remotely reconciled to fatalities across the country or that I believed that it was acceptable to let it rip," he said.
On Wednesday, he apologised at the inquiry for his handling of the crisis, saying his government had initially been too complacent and "vastly underestimated" the risks.
