Lajos Homonnai, under his original surname Hlavacsek, started his sports career at MTK, together with his brother, Márton. They soon moved to the III. ker TVE, where Lajos twice played on championship teams (1923-24), also winning the national cup in 1925. Homonnai was capped 12 times between 1922 and 1925. He retired from the national team relatively soon and as a graduate in engineering became an official of the Budapest transportation company (BSZKRT). He also played for the BSZKRT water polo squad, and later became their leader of the swimming and water polo section.