Barca were ready to let De Jong go to ease their financial problems and even agreed a fee with United in the region of €85 million including add-ons.
However, speaking for the first time since the transfer window closed, the Netherlands midfielder told ESPN he never had any intention of departing Camp Nou.
"Of course it's calmer now than during the transfer window," De Jong said ahead of Thursday's UEFA Nations League game between the Netherlands and Poland.
"But I have to say that, for me, it was always clear what I wanted. That's why I was also able to stay calm during that period."
De Jong agreed to defer a large part of his salary when he signed a new contract with Barcelona in 2020, which means for the remaining four years of his deal, which runs until 2026, the club will pay him more than they have done for the last two years.
That makes De Jong one of the highest earners at Barca, but the relationship between the player and the club grew fraught when the club looked for a way out of the contract, sending the player's camp a letter in July warning there were irregularities in the renewal signed under the previous board in 2020.
Sources close to the player said the contract was legal and claimed the letter was intended to put pressure on De Jong to either accept a move or reduce his salary.
"There were a lot of rumours and a lot happened," De Jong added.
"I can't say in detail what happened. Look, sometimes the club has different ideas than me. Sometimes those ideas collide with each other. But, in principle, it was always fine.
"Of course, it was different from other transfer periods for me. But like I said: I stayed calm because I knew what I wanted early on.
"I wanted to stay at Barcelona and my opinion didn't change. That's why I stayed calm because I knew what I wanted."
De Jong has started four of Barca's eight games this season, coming on as a substitute in the other four. For the biggest game of the season so far in the Champions League against Bayern Munich, however, he was left on the bench in favour of Sergio Busquets, Pedri and Gavi.