As a young man, de los Reyes followed his mother's footsteps by initially turning to writing as a career; his works were part of the 1887 "Exposicion General de las Islas Filipinas" in Madrid. He later became a journalist, editor, and publisher in Manila, and was imprisoned in 1897 for revolutionary activities. He was deported to the Kingdom of Spain, where he was jailed for his activities until 1898. While living and working in Madrid, he was influenced by the writings of European socialists and Marxists.