[4] In September 1906, he moved to Germany, where he began studying philosophy at the University of Jena under philosophers Otto Liebmann and Ernst Haeckel, among others.

In 1914, he moved to Vagharshapat (Echmiadzin) at the suggestion of Catholicos Gevorg V and began teaching political economy, Latin, German and history at the Gevorgian Seminary, the primary educational institution of the Armenian Apostolic Church.

At the seminary, he propagated social-democratic ideas among the students, including Anastas Mikoyan and Aghasi Khanjian, who later became prominent communists.

[4] After the February Revolution of 1917, the seminary closed down and Hovannisian returned to Shusha, where he edited the Armenian-language socialist newspaper Nets'uk (Support).

[4] Under Hovhannisian, the ministry of education confiscated the properties of the Armenian Church in December 1920, including the museums, library and publishing house of the Echmiadzin.

Consequently, he resided in Kirovakan (now Vanadzor) and was allowed to work at the institutes of history and literature of the Academy of Sciences of the Armenian SSR remotely, between 1943 and 1954.

[11][10] While teaching at the Gevorgian Seminary in Echmiadzin in 1914–17, Hovhannisian began researching at the library and manuscript repository of the Armenian Church.

[4][6] His other notable works include Hay-rus orientats'iayi tsagman khndirë (The question of the origin of the Armenian-Russian orientation, 1921), Nalbandyanë ev nra zhamanakë (Nalbandian and his time, 1955–1956), Drvagner hay azatagrakan mtk'i patmut'yan (Episodes of the history of Armenian liberation thought, 1957–1959), and Hay-rusakan haraberut'yunnerë 18-rd dari arajin yeresnamyakin (Armenian-Russian relations in the first three decades of the 18th century, 1967).

"[12] A Soviet dissident publication noted that "[r]ather than as a political figure, he is better known as an intellectual possessing a high degree of originality, which is a rare phenomenon within the ranks of the Communist Party.

[5] His obituary was signed by Soviet Armenian leader Anton Kochinyan, long-time top Soviet official Anastas Mikoyan, World War II hero Ivan Bagramyan, and numerous scientists and scholars, including Viktor Ambartsumian, Sergey Mergelyan, Andronik Iosifyan, Boris Piotrovsky.