The 23-year-old Serbian who represented his country at this summer's World Cup in Russia, completes a permanent move to West London having spent the second half on last season on loan with the then Championship club, and was a driving force behind the Cottagers' promotion to the Premier League.
Mitrovic is now likely to play for his newly-promoted side a week on Saturday, as Fulham host Crystal Palace on their return to the top-flight this season after a four-year absence.
Fulham get their man
With Mitrovic having been away on international duty, and with the Magpies digging their heels in over a deal with their league rivals, Slavisa Jokanovic has finally got his man having been met by a summer of frustration.
With the forward dropping down the pecking order under Rafa Benitez - with questions regarding his temperament - Fulham took the number nine on loan in January, as Mitrovic spear-headed the Whites promotion run, scoring 12 goals in 15 appearances in the Championship.
Mitrovic becomes the club's fourth close-season signing for Jokanovic, having recruited Jean Michael Seri and Maxime Le Marchard from Nice, goalkeeper Fabri from La Liga side Leganes, and only last week a loan deal for Borussia Dortmund winger André Schürrle was concluded.
'Happy to the moon and back'
The Serb striker was always hopeful an agreement could be reached and having become a Fulham player permanently, Mitrovic was delighted.
Speaking told Fulham's official website: “I’m very glad and happy and proud to finally be here and officially become a Fulham player. I’m happy to the moon and back.
“I have love for the fans. They’re amazing fans and I have a really good connection with them."
Mitrovic adds, “This is a big club and last year we made history, we did big things, and I want to continue this," before finishing, "we want to keep making big things, and with all the fans behind us I think we can go far.”