Born in Vicenza to a working-class family, Gaetano Sgarabotto passed much of his extremely productive professional life in other northern Italian cities. He had two younger siblings, one of whom died in 1893, aged nine. Gaetano attended an art school from 1891 to 1896, while also learning to play the cello. By about 1898 he demonstrated an interest in making violins and other instruments; he completed a few violins that, although amateurish, met with approval and encouragement, apparently even from the Hills of London, the world's preeminent violin authorities.
In 1901 he married Ines Larghini, a singer, and the couple soon moved to Milan, where Gaetano was to perfect his skills in violin making, working under Riccardo Antoniazzi in Leandro Bisiach's workshop. He remained with Bisiach until 1905, while also building his own clientele. Gaetano's eldest child, Pietro, the future violin maker and assistant to his father, was born in Milan in 1903. After leaving Bisiach around 1905, Sgarabotto returned to Vicenza, occasionally supplying him with instruments in the white that Bisiach finished and sold.