[1][2][3] Lasciac was born to Peter Laščak and Jožefa (née Trampuš) in the Italian Gorizia suburb of San Rocco (Slovene: Podturn) in 1856.

[citation needed] After finishing primary and secondary school in Gorizia, Lasciac studied at the Vienna Polytechnic Institute.

[4] While still a student,[4] Lasciac married Maria Plesnizer (also Marija Alojzija Plesničar[5]) from a Slovene family.

Maria bore three children[6] with unusual and fully Italian names: Plautilla Angelina Francesca, Fabrizio Antonio Giuseppe and Romeo Italico Alessandro (died 1926[7]).

[11] Asteroid 292459 Antoniolasciac, discovered by astronomers at the Italian Farra d'Isonzo Observatory in 2006, was named in his memory.