The Colombia international has joined the Elland Road outfit from Dutch side Feyenoord for a reported £21m fee, signing a five-year contract.
Sinisterra is expected to fill the void that is likely to be left by Brazilian international Raphinha, who has been strongly linked with moves to Arsenal, Chelsea and Barcelona.
Sinisterra is Leeds' sixth summer signing, joining the likes of Brenden Aaronson, Rasmus Kristensen, Marc Roca, Darko Gyabi and Tyler Adams.
Sinisterra spent four seasons with Feyenoord after joining from Colombia side Once Caldas in 2018 and scored 23 goals with 14 assists across 49 appearances in all competitions last season.
The 23-year-old was named the Europa Conference League's best young player after helping Feyenoord reach the final, where they lost to AS Roma.
Speaking to LUTV on his arrival in West Yorkshire, Sinisterra said: "I am very happy to be here in this beautiful club, I am enjoying this time.
"I know it's a historic club with beautiful fans. I heard a lot of things about the stadium and atmosphere, it's amazing so I can't wait to feel that in person.
"It was my dream when I was a child [to play in the Premier League], right now I am close to making that.
"Of course I will work to bring this quality (form with Feyenoord) to Leeds. This is my feeling, that I want to do the same or even more for this team and for the fans.
"I think it is also one of my characteristics, to enjoy and make the fans happy with my skills, my quality and hopefully I can do that here at Elland Road."
Sinisterra has won five caps for the Colombia national team.
