Born in Dusseldorf, Seidel was an amateur who raced intermittently in Grand Prix for a decade with little in the way of success.
Starting with a Veritas RS in the 1953 German Grand Prix he rounded off his Grand Prix career at the 1962 British Grand Prix at Aintree in a Lotus-BRM 24. The eight Grand Prix starts separating those two events were tackled in a wide variety of cars ranging from a Scuderia Cento Sud Maserati 250F to a Formula 1 Cooper. His best finish was ninth in the 1960 Italian Grand Prix in his own Cooper-Climax T45.
Ober the winter of 1960-1961 he took part in some races in South Africa - the South African Grand Prix, the Cape Grand Prix and the Fairfield 100, driving the T45 Cooper.
In other forms of motor sport Siedel had some good results in sportscars in long distance racing driving a variety of Porsches and Ferraris. He finished second in the 1957 Reims 12 Hours with Phil Hill and third at Sebring in 1958 with Behra. It appears that he also raced for Ecurie Ecosse. His best result was a win in the 1959 Targa Florio with Edgar Barth.
In 1962 at the German Grand Prix, Seidel's Lotus 24-BRM broke down after 4 laps in practice. Altough the regulations stipulated that every competitor had to do at least 5 practice-laps, Seidel thought his hundreds of laps at the Ring in races and practices througout the years was sufficient to be allowed to start. But the organizer, AvD, refused. The German newspaper MITTAG made a story on this, in which Seidel harshly critisized AvD, and even his fellow racers Heini Walter and Bernard Collomb.
For this he was stripped of his membership in AvD. Later ONS took away his racing licence for life. This was soon shortened to two years. However without the right papers Seidel took part in the Mexican GP that same year. Following this, his case was brought before the CSI. Seidel's entry in the Mexican Grand Prix in November 4 1962 was his last apparance. Interestingly, his car, a Lotus 24-BRM, chassis number 946 next appeared in the Gran Premio d'Imola, April 21 1963, this time driven by Gunther Seifert. The entrant was Autosport Team Wolfgang Seidel. Seifert raced it once more for Seidel, at Siracusa on April 25 1963.