[3][4] He had a younger brother named Ernő, a journalist, who ran a revisionist media agency in Amsterdam.

[7] He represented Hungary in one Davis Cup tie, playing doubles alongside Béla von Kehrling and subsequently lost to Jean Borotra and René Lacoste in 1925.

In 1927 he was drafted into the international team challenge between Hungary and Austria and won the doubles tie partnering Pál Aschner against the pair of Herbert Kinzl-Mayer.

[6] He was awarded the title of Oberregierungsrat (a senior administrative position) by Hungarian Governor Miklós Horthy in 1930 for his sport merits.

The case, better-known as the Equine nutrition-panama, was a military concession affair, where Kelemen's firm supplied the army with horse nutrition and allegedly bribed logistics officers to bypass the shipment regulations.

[14] The case was closed in December 1930, all charges against Kelemen and his business partner were dismissed, although many high-ranked military officers were sentenced to several years in prison.