The former PM submitted written evidence outlining his defence – funded by taxpayers to the tune of £220,000 – to MPs on the privileges committee on Monday and the contents were made public on Tuesday.
In the 52-page dossier, Johnson said that while MPs were misled over gatherings at 10 Downing Street, he did not "intentionally or recklessly mislead" them.
He also said he takes "full responsibility for everything that took place on my watch", but also slammed the committee's interim report as "highly partisan" and suggested the committee itself was "absurd and illogical".
His comments come ahead of an evidence session in which Johnson will face off against MPs on Wednesday, in a meeting that could capsize his political career.
The former prime minister also submitted WhatsApp messages that suggest he was "advised rules weren’t breached" and there was a "general assumption" the gatherings complied with COVID rules issued by Johnson's government.
The then-prime minister attended a series of gatherings at Downing Street during lockdown – one of which was a birthday celebration for Johnson himself.
After pictures and emails emerged suggesting such events had taken place, Johnson told parliament: "Those were people at work, talking about work."
Johnson claims he didn't spend more than 25 minutes at the events and believed he was complying with the rules while he was there.
A report into Partygate by senior civil servant Sue Gray found "a failure of leadership and judgement" by Johnson, but was dismissed by his allies as a "stitch up" after she was offered a role as chief of staff for Labour leader Keir Starmer.
Read more: Johnson ally warns ex-PM could face parliamentary ‘witch hunt’ over Partygate (PA, 5-min read)
What happens if Johnson is found to have lied to parliament?
The seven-member cross-party privileges committee, which includes four Tory MPs and is chaired by Labour MP Harriet Harman, will decide whether Johnson misled parliament, and whether his doing so was "reckless or intentional".
Johnson said in a statement: "It is clear from this report that I have not committed any contempt of parliament.
"That is because there is no evidence in the report that I knowingly or recklessly misled parliament, or that I failed to update parliament in a timely manner."
If the committee finds he was in contempt of parliament, Johnson faces sanctions including a 10-day suspension from his parliamentary seat – which could in turn throw his political future into jeopardy.
A 10-day suspension from parliament is enough to trigger a recall petition – meaning his constituents in Uxbridge and South Ruislip could force a by-election, with the possibility that Johnson could lose his seat.