Manchester United and other top European clubs were reportedly interested in signing the highly-rated teenager.
Haaland established himself as one of the best players in Salzburg since his arrival from Molde FK in January.
The Norway striker has been in fine goal scoring form for the Austrian Champions, having scored 28 goals in 22 appearances, eight of which came in the Champions League group stages.
In a press release issued by Dortmund CEO Hans-Joachim Watzke, the German revealed the club’s excitement of landing one of the most coveted players in Europe.
He said: “Despite interest from many other top clubs in Europe, Erling Haaland has opted for the sporting challenge that BVB is able to offer as well as the opportunities we presented him with. Our persistence has paid off.”
The club’s Sporting Director Michael Zorc added: “We can all look forward to welcoming an ambitious, athletic and physically strong centre forward who has a nose for goal as well as impressive pace.”
“We want to improve him as a player at Dortmund. At 19 years of age, he is of course still at the beginning of what will hopefully be a glittering career!”
Haaland insists the idea of playing in Signal Iduna was one of the reasons he joined Dortmund.
He said: "There was a feeling right from the start that I absolutely wanted to switch to this club, go this route and play football in this incredible Dortmund atmosphere in front of more than 80,000 spectators. I'm already burning for it."
"I had intensive discussions with the club management and the sports management, especially with Hans-Joachim Watzke, Michael Zorc and trainer Lucien Favre."
