Uccellini's life, like many composers of the 17th century, is not well documented; however, enough information exists to create a rough biography. He was born into a reasonably affluent noble family in Forlimpopoli, Forlì, who had owned land in the area since the early 14th century. Many members of the family held ecclesiastical posts locally, including Uccellini's father Pietro Maria, and it is likely that Marco went to study at the seminary in Assisi sometime in the early 1630s. Evidence from his will suggests that Uccellini began his formal musical education there, possibly under another notable early violinist-composer, Giovanni Battista Buonamente, who was then serving as music director (maestro di cappella) at the Basilica of Saint Francis of Assisi.