After the mobilization in 1915, he was appointed Head of the Operations Department at the headquarters of the acting army in Kyustendil.

After the death of Major General Konstantin Zhostov in August 1916, he became Chief of Staff of the Bulgarian Army.

In February 1917, due to conflicts with the Allies, he was sent to command the 2nd Bulgarian Army.

In September 1918 he was part of the Bulgarian delegation that signed the Armistice of Salonica, together with Andrey Lyapchev and Simeon Radev.

Lieutenant General Ivan Lukov died on April 17, 1926, in Sofia, Bulgaria.