Born in Bex in the Canton of Vaud, Eyer studied in Lausanne, Geneva and Neuchâtel and taught sport disciplines in Vevey.
Eyer taught physical education in Lom (1894), Silistra (1903) and Rousse (1909) and was the main coach of the Yunak sports associationsaround the country.
When the Balkan Wars broke out, Eyer, despite being a foreign citizen, regarded the protection of his second homeland as his duty and enlisted in the Bulgarian Army as a volunteer.
[2] After Bulgaria joined World War I, Eyer again enlisted as a volunteer as an officer in the 38th Infantry Regiment.
He died on 2 September 1916 during the Battle of Doiran, and was buried in the village of Čaušli, today in North Macedonia.