The son of the painter and illustrator Roberto Focosi, Alessandro completed his artistic training at the Brera Academy of Fine Arts, where Francesco Hayez was his master. The winner of numerous academic prizes, he also received a grant from the Brera that enabled him to visit Florence, Rome and Turin for study purposes over the period 1858–60. The 1860s saw him specialise in Romantic treatments of historical and literary subjects that were widely praised and received official recognition. He was made an honorary member of the Brera Academy of Fine Arts in 1863. In addition to the exhibitions of the Brera Academy in Milan and the Promotrice in Turin, his works were also shown at the Universal Exhibition in Paris in 1867 and the Munich Exhibition of Fine Arts in 1869.