Kremers began his football career as a youth player, along with his brother, at Borussia Mönchengladbach before eventually going on to make over 20 appearances for the first team in the Bundesliga. After two years at the club he (and his brother) moved on to Kickers Offenbach where he had an impressive strike record with 10 goals in just 25 starts. In the summer on 1971 he and his brother both moved to FC Schalke 04 and it was in the following year that he got his call up to the German national team. Kremers went on to play 15 times for his country, playing in the winning 1972 UEFA European Football Championship team and he scored a total of three goals.