Gabriel Poulain's family owned a bicycle and automobile factory in St. Nazaire . Poulain first trained as a mechanic before he became a cyclist in 1902 and also promoted the Poulain brand as a professional.
In 1905 Poulain became world champion aviator on the track and took second place in 1906 and 1908. Otherwise he mostly only started in France.
Poulain was also active as a pilot and in aircraft construction. In 1910 he passed the German pilot's exam as 14th. In 1911 he took part in the long-distance flight "Gotha-Weimar-Erfurt-Gotha". He also tried his hand as a tinkerer and inventor. On July 9, 1921, he won a prize awarded by Peugeot for 10,000 francs by flying more than ten meters and higher than one meter in a self-made, human-powered flying machine in the Bois de Boulogne in Paris . The device consisted of a bicycle with two wings.
In 1924, at the age of 40, Poulain was still French champion, the following year it was enough for second place. In 1927, at the age of 43, he officially retired from cycling.
Poulain was on friendly terms with the German aviator Henry Mayer. This friendship later turned into a bitter rivalry, which often culminated in fierce verbal battles and insults. In 1909, on the occasion of another dispute, Mayer challenged Poulain to a match with a personal stake of 1,600 gold marks. Poulain agreed. At first there was no cycling track that wanted to host the duel. After all, the Paris-Vincennes railway could be won over. Poulain won the first run, Mayer the second. In the final run, the competitors practiced several long standing attempts , over a total of 207 minutes. The race stewards set deadlines for both of them to finish the race several times. Shortly before the end of the last deadline, after well over three hours of racing, Poulain offered to get off the train and finish the race without a winner. Mayer agreed, the feud was over.