Gaston Teuscher was born to a farming family settled in Montherod, near Aubonne (Switzerland). His mother, with whom he was particularly close, worked as a midwife, while his father worked on various farms. As a little boy, Gaston Teuscher already had an independent spirit and, having finished his schooling, he travelled in several European countries, teaching French and gymnastics to meet his expenses. Once back in Switzerland, he became a teacher, although he always sought out those positions granting him the most liberty. In his free time, he would travel around Switzerland by train, for the sheer pleasure of it. Upon retirement, and thanks to his rail pass, he continued to travel a great deal, at times covering hundreds of kilometers to visit a restaurant in Lucerne or Lugano. His outgoing nature enabled him to meet many people, albeit in short-lived fashion.

In 1974, at the age of seventy-one, Gaston Teuscher suddenly took to drawing. It was an activity he himself considered totally impulsive: he would execute very tiny drawings on gold or silver cigarette wrappings, or on restaurant tablecloths. Availing himself of the preexisting stains and rips in such supports, he took to drawing faces and silhouettes in lead pencil or ballpoint pen, using coffee grounds, cigarette tar, ashes and wine to heighten the colors. It was Gaston Teuscher's impression that the shapes he drew pre-existed his drawings of them, and that, in fact, he was only revealing them through his chosen process. He also darkened his works using the flame of a lighter. In twelve years — working on his train rides, in cafés or simply in the street — this prolific creator produced several thousand works.