During the Balkan wars and World War I, he was a member of the leadership of the Narrow Socialists' Organization in Sofia and of the leadership of its trade union organization. Here he opposed the Balkan Wars and World War I and was sympathetic to the October Revolution in Russia. In 1919 his Narrow Socialists joined the Comintern and were reorganised as the Bulgarian Communist Party. In 1920 Glavinov was elected as a member of the Central Emigrant's Commission to the Central Committee of the Party. He was arrested several times after the 1923 Bulgarian coup d'état. After the St Nedelya Church assault on 16 April 1925 he was arrested again and afterwards Glavinov withdrеw from active political life. He died in Sofia in 1929.