In 1936 he enrolled to the Royal Hungarian Honved Staff Academy, which was the camouflaged military university of Hungary, hidden under the name of Regulation Review Course for Officers.

In 1940, after graduation he was assigned to the 14th Infantry Brigade, stationed in Szeged, where he served as a trainee staff officer under the command of Marcel Stomm.

After the German occupation of Hungary he promoted to Major and assigned to the newly founded Szent László Infantry Division, as a Chief of Staff.

When the division sustained heavy damages in the fight around Budapest, he pulled it out from the front-line, against the orders of the German High Command and reorganised it in the area of the Lake Balaton.

Árpád Lajtos committed suicide on 25 May 1986, hours after the death of his wife, the famous Hungarian actress, Margit Dajka.