Perhaps Germany's most promising young driver of the early sixties, Ahrens Jnr began racing in 1958, aged 18, driving an F3 Cooper. He was soon beating his father (a former 250 cc German speedway champion and accomplished national car racer), notching up a dozen wins by the end of 1959. After a rather barren 1960 season with a Formula Junior Cooper, Kurt made amends the following year, defeating Gerhard Mitter to win the German Formula Junior championship, a feat which he repeated in 1963 after returning from a six-month suspension imposed by the ONS for disputing the official result of a race the previous year.
The acquisition of a Brabham in 1965 provided him with the opportunity to race in both F3 and F2 but his outings in the latter category were restricted by his commitments at his father's garage and scrap metal business. Nevertheless he also found time to race the works Fiat-Abarth on occasion with success.
Backed by Caltex (who sponsored his only F1 ride in the German GP of that year), he enjoyed a full Formula 2 season in 1968, finishing second in the Eifelrennen and third at both Jarama and Hockenheim, relishing the chance to compete with Grand Prix stars such as Rindt and Stewart.
Having previously stated his dislike of long-distance racing, it is perhaps surprising that Ahrens chose to opt for this category in 1969, winning the Austrian GP with Jo Siffert in David Piper's Porsche 917. Racing a works Porsche, he proved a reliable partner for Vie Elford, the pair winning the Nurburgring 1000 Km in 1970, Kurt's final racing season before retirement.