After officially ending his 25-year-old association with McLaren in 2014, the former CEO and team principal of the British team told himself he would stay away from Formula One and no longer watch the races.
But having been indelibly linked to the upper echelons of motorsport for so long, he was quickly tempted back to viewing from afar and grands prix remain a must watch in the Whitmarsh household.
His former team have been well off the pace this season and look set to struggle again at Montreal's Circuit de Gilles Villeneuve this weekend, but no more does Whitmarsh have to worry about every twist and turn of the two McLarens being pored over by the world's media.
Instead, the 57-year-old's feet are now firmly planted under a different desk plotting how to win sailing's America's Cup as CEO of Ben Ainslie Racing, an appointment that shocked him as much as anyone else when announced in March.
'I was surprised when Ben approached me,' he admits seven weeks into the job. 'I'd had a few other offers but I didn't want to go back to Formula 1. I didn't want F1 to define me.
'Ok, it defines great swathes of it as it took my life for 25 years. But I'd be disappointed in myself if I didn't try something else and then Ben called me.'
The pair had met on occasion at grands prix -- fellow Briton Ainslie, a four-time Olympic gold medalist, is an avid F1 fan -- but their conversations were always brief, Whitmarsh's focus on the race weekend at the time.
'So Ben came to my home and I said to him at the time it must have been his easiest recruitment ever,' says McLaren's former team principal.
'We didn't get into the specifics of a contract or money. I just said 'Ben, I want to do this', that I'd do it whatever the terms.'
By his own admission, Whitmarsh is no sailor -- although has been on the occasional large yacht such is F1's wont -- and his sole brush with the America's Cup had been talks with the Australian sailor John Bertrand about a potential tie-in with McLaren in the early 1990s that never materialized.
Like most of the wider public, his first proper introduction to the America's Cup was as Ainslie and Team Oracle produced one of sport's greatest comebacks in history to win in San Francisco Bay.
At the time, Whitmarsh was in the midst of a car testing session at Paul Ricard Circuit in France. An avid sports fan, he tried to find somewhere showing the finale but failed.
'Thankfully I had this app on my iPad so we managed to track it down and I had 10 or 15 people hunched over the iPad watching the great drama,' he recalls. 'I love sport and that was a real moment for me. I was enthralled by it.'
With a lack of nautical knowledge and no historic knowledge in the event, it begs the question why Whitmarsh so readily signed up amid a myriad of potential other job offers.
'I missed the technology and racing and competition, and it has all that,' he says. 'You can get hooked by the competition, have you done enough, are you fast enough, that sort of thing.
'Racing is going to war every time, equipped with everything you can to beat the competition. I love that.
'But also this is the first time this country in 164 years we have got a sailing team with the technical backing and the funding for the scale of budget required.
'It's a very credible challenger and my thought was that if I don't do this I'll regret it. Then there's Ben himself who's an incredible human being and competitor and also so humble.'
There is a growing F1 hub within Ben Ainslie Racing with a tie-in already in place with Prodrive boss Dave Richards, who used to front up the British American Racing team in F1, and Red Bull design guru Adrian Newey.
It was Whitmarsh that lured Newey to McLaren in 1997 to spark one of the most successful periods in the team's rich history and then the pair turned foes on the race track with Newey's subsequent move to Red Bull nine years later.
'Adrian's an extraordinary individual and I desperately wanted to beat him at Red Bull but there's always been a great respect there,' he says. 'And just because of that rivalry on track it doesn't mean you cannot have a relationship off it.
'It's the same with [former Ferrari team principal] Stefano Domenicali. Ferrari and McLaren were big foes in F1 but we're still in touch, I still see him socially.'
As for whether F1 will see Whitmarsh back in the paddock, that is highly unlikely. He has been offered repeated chances to come for the odd race weekend but has opted to stay away.
This is the first time McLaren's former boss has spoken on record about his departure from the team as Ron Dennis, who he had replaced, returned to the front line of F1.
'I've never really spoken about it,' says Whitmarsh, who took 18 months off to travel to Cuba and Mexico and visit his daughter on her work as an anthropologist in Rwanda, Uganda and Borneo.
'It reached a point that it was my decision and I left. Various things led to that that I didn't believe and didn't want. I can honestly say that it was my decision but that circumstances led to it but I haven't regretted it.
'I know some people have wanted me to speak out and criticize but I don't feel like that. I feel honored and lucky to have had 10 years in aerospace and then 25 years with McLaren.'
Whitmarsh understandably takes great pride in his role in turning McLaren from a business with less than 100 staff and a turnover of £16m ($25m) to a behemoth of a 3,000-strong workforce and a turnover in excess of £600m ($920m).
He argues his skills overseeing such numbers as opposed to the 70 to 80 staff at Ben Ainslie Racing are directly translatable. On taking up the new role, his first task was to sit down with every member of staff individual and ask if they could win the America's Cup.
And the answer? 'There's no Churchillian speech of 'we will beat them on the beaches' or should that be Bermuda [where the America's Cup will be hosted in 2017],' he adds.
'We have honest and intelligent staff that sense we have the stability of backers, the sailing team and the resources in terms of people and money that if we do a good job we can win it.
'I'd love to finish this having won at least one America's Cup for Ben Ainslie Racing.'
Read: Ben Ainslie plots America's Cup history
Read: How to build an America's Cup boat
Read: Dennis: McLaren will return to winning ways
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