After the end of World War I, Mihailov settled in Sofia and began studying law at the Sofia University where he was contacted by IMRO activists and offered to work as a secretary for IMRO's leader at that time, Todor Aleksandrov.
After the end of World War I, Mihailov emigrated in Bulgaria and settled in Sofia. Here he began studying law at the Sofia University, where he was contacted by IMRO activists and him was offered to work as a secretary for IMRO's leader at that time, Todor Aleksandrov.