Ernesto was one of several brothers who together created the Maserati enterprise, which was formally established in Bologna on 14 December 1914 under the leadership of Alfieri Maserati. Bindo Maserati, Ettore Maserati, and Ernesto were among the other brothers involved. During World War I, while his older brothers served in the military, Ernesto ran the workshop, gaining formative experience in the practical management of a racing car operation at a young age.
Ernesto began competing in 1924. He won the Italian drivers' championship in 1927 driving the Maserati Tipo 26, and again in 1930 in the Maserati Tipo 8C-2500, establishing himself as a capable racing driver in his own right as well as a builder. His victories at the national championship level gave the young Maserati marque direct competitive proof of the machinery being produced in its workshops.
When Alfieri Maserati died in 1932, Ernesto took on a triple role as director of the company, its chief engineer, and its sole works racing driver. The period placed considerable demands on him, requiring him to oversee the technical direction of the firm while also representing it on the track. Under his direction the company continued to develop competitive Grand Prix machinery that challenged Alfa Romeo and Auto Union during the 1930s.
In 1937 the Maserati brothers sold the company to Italian industrialist Adolfo Orsi. The sale did not mean an immediate departure: the brothers negotiated a ten-year contract to remain with the company in technical capacities. During this period Ernesto contributed to the design of the Maserati A6, a road and racing car that bridged the gap between the pre-war Grand Prix era and the post-war sports car competitions of the late 1940s.
When the ten-year contract with Orsi expired in 1947, Ernesto left Maserati together with his brothers Ettore and Bindo. The three founded the Officine Specializzate Costruzione Automobili, known as O.S.C.A., based in Bologna. The new firm built small, lightweight sports and racing cars throughout the late 1940s and 1950s, continuing the brothers' tradition of producing purpose-built competition machinery. O.S.C.A. cars achieved notable results in international sports car racing during this period, including class victories at prestigious events.
Ernesto Maserati died in Bologna on 1 December 1975, aged seventy-seven. His contribution to the Maserati story was foundational in two respects: he kept the workshop operational during the years when older brothers were at war, and he provided the technical continuity after Alfieri's death that allowed the firm to remain competitive through the era of the Silver Arrows. The Maserati name became one of the most storied in motorsport, and Ernesto's engineering work through the 1930s underpinned much of that reputation.