Born in Wysokie Mazowieckie in the Łomża Governorate of Congress Poland, Moscicki served during World War I in the 1st Uhlan Regiment of the Pulawy Legion.

In 1917 Moscicki was promoted to polkovnik, and on 19 July that year, at the village of Porohy near Nadworna, he was named commandant of 1st Uhlan Regiment, part of the so-called Pulawy Legion.

Five days later, Moscicki fought in the Battle of Krechowce, in which his unit defeated Bavarians of the Imperial German Army.

He wanted to get in touch with the Regency Council, but the mission failed when he was captured and killed by Bolsheviks and armed peasantry near Luninets.

Moscicki was buried in Minsk, and in 1921 his body was transported to Warsaw, where a second funeral took place at Holy Cross Church.