The 21-year-old, who worked under Leeds boss Jesse Marsch during his time in charge at the Austrian club, will formally complete his move to Elland Road for an undisclosed fee on July 1.
“Leeds United are delighted to announce an agreement with Red Bull Salzburg for the transfer of Brenden Aaronson, which will be completed on July 1, 2022,” the Yorkshire club said in a statement.
“The 21-year-old will join for an undisclosed fee on a five-year contract, running until the summer of 2027. The transfer is subject to the necessary international clearance and a work permit.”
Aaronson made 41 appearances in all competitions for Salzburg in the 2021/22 season as they won the Austrian Bundesliga and Austrian Cup.
Leeds finished 17th in the Premier League table, just one point above the relegation zone after winning at Brentford in a dramatic final-day escape.