Hamazasp Ghaltaghchyan was born in 1883, in city Kars, in the family of merchants.
In 1904 he entered the Institute of Civil Construction of Saint Petersburg. H. Ghaltaghchyan was expelled from the institute for participating in organized student anti-state strikes.
In 1907, after readmission in the institute, he graduated in 1914, obtaining the profession of architectural engineer. He was non-party. He started his work experience at an early age.
In 1899-1903, he worked as a locksmith and lathe at Tbilisi parochial college.
In 1907-1914 in parallel with the studies, he worked at a special construction bureau as a designer.
In 1914-1915 H. Ghaltaghchyan participated in the First World War, at the Turkish front of the Caucasus army.
In 1919-1923 he worked at construction department of Batumi city, as well as in the utilities division of the city as a constructor engineer, afterwards, as city architect.
In 1923, he moved to Moscow and worked at the administrative and economic department of the Kremlin as head of the construction division, later, deputy director.
In 1932-1933 he worked at the Academy of All-union agricultural academy after Lenin as an architect of agri-building.
In 1933-1935 he governed the agricultural and architectural office at the Academy of All-union Architecture.
In 1935, H. Ghaltaghchyan moved to Yerevan and till 1936 he worked at Yerevan City Executive Committee as chief architect of the capital.
From August 1936 he was assigned the director of Yerevan Polytechnic Institute and governed the institute till August 1937.