Attilio Marinoni was a test driver for Alfa Romeo who took three wins in the Spa 24 Hour race. At the end of 1932 Alfa Romeo withdrew from racing, he became their chief mechanic and reserve driver and made a few appearances in Grand Prix between 1934 and 1939. The war interceded and Marinoni was killed testing an Alfa Romeo 158/512 hybrid.
Attilio Marinoni was an Alfa Romeo test driver. In 1927 he finshed second to Enzo Ferrari in the Coppa Ciano at Moderna driving an Alfa Romeo 1500.
In 1928 he came fourth in the Mille Miglia with Giovanni Battista Guidotti in Alfa Romeo 6C 1500 Sport and then took the first of his three wins in the Spa 24 Hour race, driving with Boris Ivanowski. He also finished third in the Coupe Georges Boillot.
1929 saw him finish the Mille Miglia in 6th with Ferdinando Minoia in an Alfa Romeo 6C 1750SS spider and then won at Spa with Robert Benoist.
He came third in the Mille Miglia in 1930 with Giuseppe Campari. He raced in the Double 12 at Brooklands with Kaye Don and then won Spa for a third time this time driving with Pietro Ghersi. In 1931 he entered Le Mans with Goffredo "Freddie" Zehender in an Alfa Romeo 8C 2300. Unfortunately they crashed out on the 99th lap. He crashed the following year as well driving Prince Djordjadzé's Alfa Romeo 8C 2300 with Angelo Guatta.
At the end of 1932, as Jano was preparing a new P3 racer, Alfa Romeo decided to withdraw from racing again. Ferrari tried to get his hands on the P3s but was refused. As rivals Maserati and Bugatti had better machinery Ferrari lost all his top drivers as the team struggled on with old Alfas. Eventually Pirelli interceded and convinced Alfa to supply Ferrari with six P3's and the services of engineer Luigi Bazzi and Marinoni. Marinoni became the chief mechanic and reserve driver. Ferrari hired Luigi Fagioli and the veteran Campari to be his drivers. The team was immediately successful but at Monza in September Campari was killed in one of the cars. The same accident claimed the life of former Ferrari driver Borzacchini.
In 1934 Marinoni finished 3rd at the Marne Grand Prix and fifth in the Italian Grand Prix. The following year saw him take a 4th in the Belgium Grand Prix and another 4th in the Italian.
Carlo Pintacuda and Marinoni went to South America with Alfa Romeos in 1936. Marinoni failed to finish in Rio but in the first races held in Sao Paulo the Alfa drivers faced little opposition and Marinoni crossed the line in second place. In 1937 he drove in the German Grand Prix
He died when he crashed the Alfa Romeo 158/512 hybrid into a lorry on an open highway during the war while testing in anticipation of the resumption of racing.