[9] Agnelli was elected by the then assemblea di soci (membership assembly) as president of Italian association football club Juventus on 24 July 1923[10][11] .This was a turning point as it coincided with the switch from amateur to professional football, which became, in the words of historian Aldo Agosti, "an indicator of the deepest transformations that take place in society, imposed from above by a mass system that the fascist regime tries to create.

"[12] According to Agosti, "Juve, never truly aligned with the regime, at the time perhaps embodied a certain reactionary respectability, but showed intolerance of the showy, even vulgar displays of fascism, intercepted the change and laid the foundations for a solid club, up to today's Juve", which faced the European football changes.

[12] Upon being elected,[13] Agnelli said: "I am grateful to you for welcoming my presidency as an honour, but I hope I will not disappoint you if I confess that I have no intention of considering it merely honorary.

Under his management, which lasted until Agnelli's death in 1935, the Turinese club established itself as a major force at the national stage having won six Italian league championships of the only top-flight competition in the country, including five in a row, being the first team to do so, a national record for the next 82 years before being broken by Andrea Agnelli's Juventus.

[15] Agnelli died in a plane accident on 14 July 1935,[9] when he was returning from Forte dei Marmi in his father's seaplane, a Savoia-Marchetti SM.80 piloted by Arturo Ferrarin, en route to Genoa.