He was mobilized in 1917-1918 as a reserve lieutenant for the 13th Infantry Regiment "Ștefan cel Mare", participated in the heavy battles in Mărăști and Mărășești and was awarded the medal "Commemorative Cross of the 1916–1918 War with the Marasti strap". Ion Negrescu was the Mayor of Chișinău in two legislations (1928-1931), then, the secretary general of the Ministry of Bessarabia (1932-1935).