From 1907 onward, Charles Moureu was a professor of chemical pharmacy at the École supérieure de Pharmacie in Paris.  In 1913 he was named director of the laboratory of hydrological physical chemistry at the École pratique des hautes études. 
He became a member of the Académie Nationale de Médecine (from 1907), Académie des sciences (from 1911) and Académie nationale de pharmacie (president 1913).
After the use of poison gas against French troops in the Second Battle of Ypres on April 22, 1915, Charles Moureu was appointed vice-chairman of France's Committee for Gas Warfare. Moreu headed the Section des produits agressifs (Aggressive Products Section). In this role, he was responsible for 16 chemistry laboratories in Paris, supervising and coordinating their work until 1918. He was also involved in conferences of the allied powers in September 1917, March
1918, and October 1918.
In 1917 Charles Moureu was appointed professor of organic chemistry at the Collège de France. Succeeding Émile Jungfleisch, Moureu was the only professor to be appointed to the college during the first world war.
Moureu supported initiatives for international cooperation and standardization among chemists. He served as a vice-president of the Société chimique de France  (SCF) in 1910.  
Moureu was active in the restructuring of chemical organizations in 1918–1919. The Allied Conference of Academies formally dissolved the International Association of Chemical Societies (IACS), as of July 22, 1919. Moureu was the founding President of the International Union of Pure and Applied Chemistry (IUPAC), holding the position from 1920 to 1922. He also supported the establishment of the Maison de la chimie in Paris as an international center for chemists.
In 1921 and 1922, Moureu visited the United States as a scientific expert. In 1921 he was part of a French  Mission on Disarmament.
In 1922, he visited Washington, D.C. for discussions on the use of gas in warfare. He visited a number of universities in the United States and Canada, and was given an honorary degree by the University of Montreal.
Moureu became chairman of the French Committee of National Defence when it was established in 1925, leading it until his death in 1929.