The 24-year-old U.S. international joins Wolfsburg after five seasons with Hertha, signing until 2022 at the Volkswagen Arena.
Several outlets have put the transfer fee at €20 million ($22.5 million), breaking the previous record of $13 million when Jozy Altidore joined Sunderland from AZ in 2013.
A Hertha academy product, Brooks made 24 appearances as the club finished sixth in the Bundesliga during the 2016-17 campaign.
The Berlin club also commented on the move, with general manager Michael Preetz quoted by Kicker as saying: "We do not want to let him go because he is a family. But we have found a solution that is also for the benefit of Hertha BSC."
The World Cup veteran has compiled 30 caps since debuting for the U.S. in 2013, including five starts at the Copa America Centenario last summer.
Brooks currently is in camp with the U.S. squad ahead of Saturday's friendly against Venezuela in Sandy, Utah.