Haaland has scored 36 Premier League goals in his debut season in England, helping Manchester City to win their third straight title.
The 22-year-old Norwegian has struck 52 times across all competitions.
Haaland's goals have helped Man City's bid to land a treble this season.
Pep Guardiola's side have reached the FA Cup final, where they will take on Manchester United, and will play Inter Milan in the Champions League final on June 7.
Haaland is the first player to win both the best player and best young player in the same season.
"I am honoured to have become the first player to win both awards in the same season - thank you to everyone who voted for me," said Haaland.
"It has been an incredible first season in the Premier League and lifting the trophy last weekend in front of our fans at the Etihad was a very special moment for me," added the former Borussia Dortmund striker.
"These awards would not have been possible without my amazing team-mates, the manager and all of the staff at the club who help me perform on the pitch," said Haaland.
"Now we have two more finals to go and we want to finish the season strong."
Haaland has already won the Football Writers' Association Player of the year award.
