The new national centre for English football officially opened its doors last October and has been openly praised from many quarters.
Sheepshanks is delighted with how all the England squads from the seniors down have already enjoyed the facility in Burton, but he has warned not to expect instant results.
"We have always made it clear this was a long-term project," Sheepshanks told Sky Sports News.
"We are here to invest in English football, in the future. The Premier League and clubs are more concerned with immediate results but we believe the right investment is first to give England a dedicated home, which they have never had.
"The idea that Manchester United, Arsenal, Chelsea, Manchester City - our elite teams in this country - would operate without their own training home is unthinkable yet somehow with England we have had to do that.
"But now we have and this is going to make a huge difference to all the teams when they come here.
"We had England, U21s and U19s at once and it was exciting and is gratifying for everyone who worked on this project to see it work."
Sheepshanks underlined that coaching is uppermost in their thinking.
"It is also the home of coach education and we have to give that time for it to work to invest in coaching as the Spanish did in the late 90s.
"They realised those benefits some 10 years later - and like with France when they built Clairefontaine in the 1980s and won the World Cup in 1998, we are looking for the 2020s for the real benefits of St George's Park to be felt in the game."
Whilst being the home for England's football, they have also welcomed other sports to the complex, and currently the England Rugby Union squad are using it.
"We have the England senior rugby team in training," he added.
"It is with great excitement to see all types of elite sport even though we are predominantly football but it is good to get cross pollination of all elite sports."