De Ligt came through Ajax's famed academy and enjoyed a rise to prominence at a very young age, earning a promotion to the first-team squad soon after his 17th birthday.
He then became the club's youngest captain as an 18-year-old and last season played a pivotal role in Ajax's journey to the semi-finals of the Champions League, before they were eventually eliminated in dramatic fashion by Tottenham.
An impressive physical specimen but also technically gifted for a centre-back, De Ligt appeared to have a litany of clubs vying for his signature last year, with Barca – who signed his Ajax team-mate Frenkie de Jong – seemingly the ideal fit.
But Juve made their move to inject developing talent into their aging backline, and De Boer concedes Turin was not the destination he had in mind for De Ligt.
"Clubs closest to the Ajax system like, Man City and Barcelona were interested," De Boer told Gazzetta dello Sport.
"It would have been easier to adapt. I thought he would have made a different choice, but I respect the decision very much."
Despite making a choice that might have taken De Ligt out of his comfort zone, De Boer remains confident he will be an era-defining defender.
"I was working in the academy of Ajax, I immediately liked his character: serious, intelligent, kind, he never complains, he works hard and learns," De Boer said
"And then he always had the skills of the great defender. He understood where the danger was coming... I remember him at under-14 level, when he returned from the following year 30 centimetres taller. He will be one of the best of this era, sure."