Sebastiano Albertis was born in Milano in 1828. He became a promising student of the Brera Academy, he follows the teaching of the history painter Roberto Focosi and of the genre painters Domenico and Gerolamo Induno; with the latter especially he will maintain a constant relationship of friendship and cultural exchange.

After participating in the events related to the Risorgimento he returns to Milan, resumes painting, successfully participating in the Brera exhibitions. In 1855 he created "A reconnaissance of Piedmontese cavalry outposts", the first work of the series of that patriotic military genre, which soon became his specialization.

At the outbreak of the second war of independence in 1859, he enlisted in Garibaldi's Cacciatori delle Alpi, together with the sculptor A. Tantardini, the poet A. Picozzi, A. Carissimi, E. Bezzi, A. Nullo and G. Missori. In 1859, he joined the Società de la Confusion with T. Cremona, V. Bignami, E. Pagliano, in the context of the Scapigliatura movement, a context that changed his painting towards popular themes of contemporary life. He also discovers the technique of sketch and watercolor where, in emulation with A. Durini and T. Cremona, he becomes a real master to be considered the Italian Constantin Guys.

Sebastiano continues his life as an artist and fervent patriot, committed to arms alongside Garibaldi, exhibiting in Brera and attending the Milanese aristocacy that has always paid him the highest esteem. He died in Milan on 29 Nov. 1897 and was solemnly commemorated by the old Garibaldi friend E. Guastalla