From January to July 1940, he was a courier in the prison cell of the ZWZ (organized by Captain Zygmunt Hempel and Halina Starczewska-Chorążyna, later headed by Kazimierz Gorzkowski).
In March 1941, together with his team, Zawadzki entered the Grey Ranks and took command over the Upper Mokotów Troup in the South District of the Warsaw Banner.
For the largest number of "anchors" painted in his district, he was awarded the honorary title "Kotwicki" (Anchor-man) by the Commander-in-Chief of "Wawer" Aleksander Kamiński.
As a result of the reorganization of the Warsaw Banner of the Grey Ranks in November 1942, under the alias "Tadeusz", Zawadzki became the troup leader of the "Center" hive, the commander of the Warsaw Banner Assault Groups (consisting of 4 troops), and at the same time the deputy of Lieutenant Ryszard Białous "Jerzy" – military commander of the GS, i.e. the Special Unit "Jerzy", one of the dispatching units of Home Army Kedyw (Directorate of Diversion) which established at that time.
In the last days of April 1943, at his father's request, Zawadzki wrote a short report describing the activity of "Orangery" and the Grey Ranks, as well as the course of events during Operation Arsenal.
[2] He was arrested accidentally at the end of June or the beginning of July 1943, and spent a week or two in a correction labor camp at Gęsia Street ("The Goose house").