After the graduation of University Parvanov was sent to the Institute of History of the Bulgarian Communist Party to work as a researcher and he simultaneously enters the Bulgarian Socialist Party (BSP). In 1989, a year earlier, having defended doctoral thesis on history became a senior research worker. There were historical researches on early social-democratic movement in Bulgaria. Being very much aware of issues of creating the parties he was able to become a true leader and organizer of the Socialist Party in the new political environment. Humanitarian education and great erudition were most welcome.
Parvanov’s political service record is quite an extensive.