The 17-year-old - hailed as one of Germany's top prospects - has agreed a January move to the BayArena despite being linked with Bayern Munich and Chelsea.
The 17-year-old attacker had been linked with a host of European heavyweights, with Bayern Munich and Borussia Dortmund thought to be keen on his signature, as well as Premier League giant Chelsea.
The Germany youth international has now agreed a five-year deal with Leverkusen and will complete his move in January, with the club announcing the deal on its official website.
Sporting director Rudi Voller believes the capture of the Germany youth international proves the BayArena outfit is able to attract the very best talent.
"Julian Brandt is one of the most talented players in German football," he told the club's website. "His signing is a great investment in the future of Bayer Leverkusen."
Brandt made his debut for the Germany Under-19 side in this autumn's European Championship qualifier against Belarus, while he also played in the win over Latvia and the 1-1 draw with Scotland.
He previously amassed 17 caps for the U-17 side, scoring four goals.