And with McLaren set to face the sport's governing body, the FIA, on 29 April to answer charges of breaching the International Sporting Code, Dennis admits his departure will be welcomed by two of F1's biggest names.
"I admit I'm not always easy to get on with. I admit I've always fought hard for McLaren in Formula 1," he said.
"I doubt if (FIA president) Max Mosley or (F1 supremo) Bernie Ecclestone will be displeased by my decision."
However, Dennis, who first took over as McLaren team principal in 1981, insisted at a news conference that the timing of his departure from F1 was "purely coincidental" and not linked to the team's upcoming FIA hearing.
McLaren were found guilty of misleading race stewards following the Australian Grand Prix, which led to Lewis Hamilton - who had been awarded third place - being disqualified from the race and stripped of his points.
Jonathan Legard on Dennis departure
Hamilton subsequently apologised for his involvement in the incident, claiming he had been told to lie by sporting director Dave Ryan, who was suspended and then sacked within 24 hours of the FIA's announcement of its findings.
New team principal Whitmarsh also confirmed on Thursday that he offered to quit.
BBC sports news correspondent Andy Swiss reported: "There has been speculation about Ron's reasons for leaving and I asked him whether he knew about Ryan's and Hamilton's decision to mislead stewards. He said he didn't know anything.
"I then asked whether he was leaving F1 to improve McLaren's chances at the hearing and he said 'no'.
"I also asked him about relationship with Hamilton and his father Anthony, because there were reports that it was not as strong as before. He said this wasn't the case. He revealed he had spoken to Lewis and his father a few days ago in Australia. He also praised Lewis' public apology following the incident in Australia."
There will, inevitably, be some things I will miss about him and I won't miss other things about him
McLaren F1 Team principal Martin Whitmarsh
Dennis went to to explain in a statement: "I passed the role of team principal to Martin on 16 January, the day of the launch of our new Formula 1 car. That day I was asked many times whether I would attend the 2009 Australian Grand Prix. My answer was 'yes'.
"I duly attended it - albeit not as the person in charge of Vodafone McLaren Mercedes. It was, I admit, a strange feeling.
"The next race, the Malaysian Grand Prix, I watched on TV in the UK - an activity I found surprisingly easy. I'd expected to be more emotional about it."
Whitmarsh, who was previously just the CEO of the F1 operation, said there were times both he and Dennis did not see eye-to-eye.
"Ron is an immensely complex individual," he said.
"Nobody would doubt his passion for this sport and team. There will, inevitably, be some things I will miss about him and I won't miss other things about him. He would say the same about me."
He also suggested that Dennis' departure may improve the team's standing with the FIA.
"Anyone who's looked at the relationship between McLaren and FIA over the last few years would conclude that it needs to be a healthier and more constructive one," added Whitmarsh.
Dennis first became involved in F1 in 1966, at the age of 18, working alongside driver Jochen Rindt at the Cooper Formula One team.
There followed a three-year spell with Brabham prior to Dennis working on a number of projects in Formula Two and Three for a decade.
However, Dennis longed to return to F1, and in 1981 the opportunity eventually arose with McLaren, with the then 34-year-old assuming full control, building it up into the company it has become today.
Although the global credit crisis has had a major impact on the car industry, Dennis is determined to plough ahead with his plans for a revolutionary new sports car.
McLaren Automotive is intending to raise fresh equity, in addition to the existing investment in the business, to complete the development of the planned vehicle programmes.
Dennis added: "With planned additional investment in the company of £250m, proposals in place for a new McLaren car production facility in the UK, and the potential for up to 800 skilled jobs, McLaren Automotive's expansion will represent a significant investment in the UK automotive industry."
On June 1, Richard Lapthorne, currently chairman of Cable and Wireless, will be appointed non-executive chairman of the McLaren Group, and a non-executive director of McLaren Automotive.
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