In 1917, he handed in his resignation, left Switzerland and joined the Bulgarian Army as a soldier of the Macedonian-Adrianopolitan Volunteer Corps.

After the war, Radev was Bulgarian minister plenipotentiary in The Hague, Ankara, Washington, D.C.,[2] London[3][4] and Brussels.

[1][5] In 1923, he married the Bulgarian painter, Bistra Vinarova and the couple subsequently had one son, Trayan Radev (bg).

Some of his articles were published in the book Insights into the Literate and Arts and Personal Memories, released in 1965 and provoking a significant interest.

Simeon Radev died aged 88 in the Bulgarian capital Sofia on 15 February 1967, only several days after his last book Early Memories was ready for printing.