He wanted to change the way English football thought.
The former Football Association chairman had spent years studying how other football nations developed their players and coaches, and he believed England had fallen behind.
France had Clairefontaine. Spain had its national centre in Madrid. Italy had Coverciano. The Netherlands had Zeist.
England had nothing comparable.
Speaking to Football Presse, Sheepshanks explained that creating a home for the national teams was the first step in a project designed to transform the country's football culture.
"One of the primary objects of building St George's Park was to build a training home for England teams," he said.
"We were the only ones who didn't have one.
"I was determined that we would turn that somehow to our advantage."
Rather than simply copy existing facilities, Sheepshanks wanted England to learn from the best.
"We went and learned from all of the other places that had built centres.
"Other clubs, top Premier League clubs, clubs around the world.
"We approached it as though, if you were building a centre now, what would you do differently?"
That research shaped the final design.
"We consulted like crazy with all of the stakeholders to make sure we didn't build what we thought we should build.
"We built what they wanted."
The result was a national football centre designed not only for England's senior teams but for the entire football pyramid.
For Sheepshanks, the key was creating an environment where generations could mix.
"Under-18s and under-19s could play or practise alongside senior internationals.
"Coaches could pick out the most promising young player and say, 'come and play with us this morning.'"
It was also designed as a place where coaches could share ideas.
"I used to call it a safe place to meet the enemy.
"We might want to beat the hell out of each other on the pitch, but we actually get a lot more out of sharing experiences."
The results on the international stage have been significant.
Since St George's Park opened in 2012, England's men's and women's teams have enjoyed unprecedented success, with senior tournament finals and victories across age groups.
Sheepshanks believes the first part of the mission has been achieved.
"That first reason of England teams has largely been ticked because we are regularly now getting to finals and semi-finals.
"The women's team have won the Euros twice. The under-21s have won twice under Lee Carsley."
But the second part remains unfinished.
For Sheepshanks, St George's Park was always about more than pitches and buildings.
It was about producing better coaches.
"We always knew this would take much longer.
"It would be a generational thing."
The challenge was moving away from traditional methods.
"Moving from the old-fashioned command and tell of coaches to the modern method of engagement and treating every player as an individual rather than treating them all the same."
His ambition remains huge.
"I had a vision, and it's in my book, that eventually St George's Park would be kind of the Oxford and Cambridge, or the Harvard, of coach education."
The idea was simple: becoming qualified at St George's Park should carry the same prestige as the world's leading sporting and academic institutions.
"If you wanted to get to the very top, you made sure that you did your qualifications at St George's Park."
Sheepshanks admits that vision has not fully arrived yet.
"That's a bit utopian, but you've got to start with a big dream."
The shortage of English coaches working at the highest level remains a concern.
"If you're selecting the top English coach to be the England coach, you're fishing from a very small pool."
However, he believes the foundations are stronger than ever.
The influence of St George's Park can be seen not only in England's results but in the philosophies of coaches such as Gareth Southgate.
Southgate, in particular, represented the pathway Sheepshanks hoped the centre would create.
"It was probably half by design and half by luck," he said.
"Gareth is a lifelong learner.
"He is curious and he wants to encourage others who work with him to be the same."
For Sheepshanks, the greatest success of St George's Park may not be a single trophy.
It is the change in mindset.
"When you go there, you don't think, 'I've got to spend another three or four days at St George's Park.'
"You think, 'I'm going to be stimulated, I'm going to learn something and I'm going to enjoy it.'"
That was the dream when the project began.
A place where English football could improve every day.
Keep following our 5-part series with David Sheepshanks this week as part of the promotion for his new book, 'Man on a Mission'. Available here.
