[2] In 1921, Faist joined the FC Phönix athletics department, which was re-established that year, becoming one of the club's best sporting talents, with coach Georg Amberger leading him to great success.

[2] FC Phoenix's successful 4 x 100 meter relay team (Alex Nathan, Faist, Kurt von Rappard, Robert Suhr) was nicknamed "the flying Karlsruhers" in the press.

[2] As one of the most successful sprinters of the Weimar Republic's middle years, Faist was a member of the German national athletics team in 1925 and 1926 and was considered a candidate for participation in the 1928 Olympic Games, but he was prevented to do so due to an injury.

[8] Despite being his first time outside of German football, Faist adapted quickly and after losing his first two games to Yugoslavia and Romania, he led Bulgaria to a 2–2 draw against the B team of the then world champions Italy in a friendly match on 17 May 1931.

[4][9] He then won three competitive games in a row, two of which for the 1931 Balkan Cup, a 5–1 trashing of Turkey, and an epic 3–2 victory over Yugoslavia after being 0–2 at half-time; two impressive performances that sealed Bulgaria's first-ever piece of silverware,[4][10] for which he was awarded the Grand Medal of Honor from the Bulgarian Olympic Committee.

[5] For the 1937–38 season, he was hired by Rot-Weiß Oberhausen, where the "excellent sports teacher" could not meet expectations, mainly due to a series of injuries among his squad, which was already far too small, and he was dismissed in the fall of 1938.

Only when he was fleeing the Eastern Front and retreating from the advancing Soviet army, did the experiences of hardship and misery of the civilian population as refugees make him realize that the regime of the Third Reich was a criminal one, writing in a field post letter that his enthusiasm for National Socialism had evaporated.