Lopetegui has moved to West Ham to succeed Europa Conference League winner David Moyes.
Brady told whufc.com: "There is now a great feeling of excitement and optimism around the Club as we prepare for a fresh new start this summer.
"We are delighted to have appointed Julen Lopetegui as the Club’s new men’s Head Coach – he is someone with fantastic pedigree, experience, and success in his career.
"The former Spain, Porto, Real Madrid, and Sevilla coach joining us marks the next step in West Ham United’s new and growing football strategy, which gained pace in the summer of 2023 with the arrival of Tim Steidten as the Club’s Technical Director.
"We believe Julen’s appointment will ensure a strong opportunity to build on the positive progress made in recent seasons, helping the Club to move forward in the direction that aligns with our ambitions."