Manchester City boss Pep Guardiola branded Bielsa, who has also had spells coaching in Mexico and Spain, as well as with the Argentina and Chile national teams, as “the best coach in the world” last year.
Leeds sacked Paul Heckingbottom in June after just four months in charge, revealing at the time their desire to appoint a more experienced coach for the 2018-19 campaign and beyond.
“I am thrilled to welcome Marcelo and his staff to Leeds United,” Radrizzani said.
“He is a coach that I have admired for many years and when the opportunity arose to bring him to Elland Road, we made it our top priority for the summer.
“Marcelo has a wealth of experience and he will use that to create a new culture and a winning mentality at our football club.”