Growing up in Tuscany, Donati joined his hometown club Lucchese in 2003 as a 13-year-old. By the time he was 18, Donati was scouted by world-famous club Inter Milan.
He originally signed with the U20 youth team, but it only took one season for Donati to be performing in friendlies with the first-team.
But instead of staying to fight for his place at the San Siro, Donati took a risk by leaving Italy for Bayer Leverkusen.
The €3m move paid off as Donati broke into the Bayer first-team over three seasons.
Asked byTribalfootball.comwhy he decided to leave Inter, Donati said: "Because the club had other plans and I wasn't part of these, otherwise they could have kept me, especially after the championship I played with the Under 21.
"On the contrary, they found an agreement with Bayer Leverkusen: I was very happy and I thank them, indeed, for having given to me the opportunity to play the Champions League, to go to make an experience abroad after a season spent with the youth team.
"I had the chance to see different types of football and I played in a system where the right back plays often forward, not blocked in defence; a wonderful experience."
And the 29-year-old said it was a wonderful experience picking up tricks from 'the Special One'.
Quizzed on his time with Mourinho and Rafa Benitez, Donati continued: "I didn't have a chance to speak with Benitez, but I had the honour and the pleasure to be part of the Mourinho's squad in that wonderful season of the Treble.
"So I spoke with him and I could train with the first team, stealing some little secrets."
Another youngster coming through the ranks alongside Donati was Mario Balotelli.
The talented but volatile forward featured heavily under Mourinho and helped Inter win three straight Serie A titles, as well as the Champions League.
And Donati has revealed that he has remained friends with the 29-year-old.
"Sincerely, I haven't followed much Balotelli, but I'm happy that he came back to Italy too, in his hometown Brescia.
"We met sometimes, because we have remained friends, having played together in the Primavera and having spent the summer holidays together in Forte dei Marmi sometimes.
"About his career, it's not up to me to judge him, he is surely a champion that has played with very big clubs: so I think he's happy with what he's done."
And when asked if his former side can win the title this season, Donati concluded: "This is a very interesting season and I think that Inter will try to win the Scudetto until the last minute, knowing also the personality and character of Conte."