Branco has put pen to paper on a one-year deal and could make his debut in the Sunday's friendly match against Everton at Tynecastle.
The 26-year-old told Hearts' official website: "I had seen Scottish sides in Europe, particularly Celtic and the Scottish national side and when I was aware of Hearts' interest I read up quite a bit about them and saw that they won the league by a huge margin over Rangers so I was very impressed.
"I am very much looking forward to living in Edinburgh. As soon as I knew Hearts were interested in me I was on the internet looking at the city and it is beautiful and so full of history. My wife is also very excited to be coming to live in Scotland.
"Robbie Neilson was very impressive and he explained to me his ambition for the club, where he expects us to be in the future and how he wants the team to play.
"I believe I will bring good experience from my five years playing in the Portuguese first division and in the Europa League. I want to help the club challenge in every tournament we play in and I want to help my new team-mates.
"I am a leader, I play aggressively and with a lot of passion and I like to have the ball at my feet and play from the back. From what I have seen this is the Hearts way. I'm also hoping to score some goals as I'm good in the air."