After persistently evading questions from national media and dodging a barrage of criticism, the former Conservative party leader has released a statement on Sunday night to reiterate that he had "not broken any rules".
Through David Cameron, Greensill looks to have had the run of Government from Number 10 down, including access to millions of pounds of public money.
Mr Cameron was prime minister between 2010 and 2016 before being hired as an adviser by Greensill in August 2018.
The Former PM also challenged the recent allegations creating a "false impression" that Lex Greensill, the head of the firm, was a senior member of his Downing Street team during his time in office.
"The truth is, I had very little to do with Lex Greensill at this stage - as I recall, I met him twice at most in the entirety of my time as prime minister", Mr Cameron said.
"There have been various charges levelled against me these past weeks, mainly that I made representations to the Government on behalf of a company I worked for".
"This was at a time of crisis for the United Kingdom economy, where everyone was looking for efficient ways to get money to businesses".
The company's collapse has left Sanjeev Gupta's steel empire and thousands of United Kingdom jobs in peril because Greensill was Gupta's main lender.
Mr Cameron wanted Greensill, who he was working for, to be able to issue loans using taxpayer cash through the scheme.
"We need to know what he "pushed" his officials to do to help Greensill access one of his COVID loan schemes".
The Financial Times and The Sunday Times newspapers have reported that Cameron contacted ministers directly to lobby on behalf of the firm.
But it could not be immediately confirmed whether the lobbying did lead to the Treasury reconsidering its move to reject the loan scheme application.
Greensill Capital was the only supply chain finance firm approved to administer the CLBILS scheme.
Before becoming prime minister Cameron said corporate lobbying was the next big political scandal waiting to happen.
While there is no love lost between Boris Johnson and David Cameron, and it is pretty much impossible to think of a similar case where a serving PM commissions an investigation into one of his predecessors, Labour is already warning that it could be a "Conservative cover-up". "Engagement with business, including the private lobbying by Cameron, will be covered by the Boardman inquiry", the spokesman said. The Registrar of Consultant Lobbyists concluded that the former premier did not need to register because he was an in-house employee with Greensill as opposed to a paid lobbyist.
Rachel Reeves, the shadow chancellor of the Duchy of Lancaster, said: "It is crucial that the former prime minister appears before parliament so that all the information is brought to light".