The family name may have been originally François; we find the earliest known ancestor under both names. Pierre François or Foucault lived in the parish of St-Michel-de-Rivière in the village of La Roche-Chalais in the Dordogne, where in 1641 he married Peronne Borda or Bordat. They had a son named Jean Foucault about 1641; he was baptized in the church of St-Michel-l'Écluse-et-Léparon (pictured above) and emigrated to Québec sometime before 1671, when he married Élisabeth Provost or Prévost (a "fille du roi") in November at Québec city.

They had at least four children: Denis (married 1697 Catherine Pelletier dit Antaya); Françoise (married 1701 Jean-François Lemire); Gabrielle (1682?-1751, married 1700 René Lefèbvre); and Jean-Baptiste (married 1708 Marguérite Bergeron and 1732? Marie-Anne de Gerlaise).

Jean-Baptiste Foucault dit Courchêne and Marguérite Bergeron were the parents of Marie-Madeleine (1712?-1770), who married Joseph-Michel St-Germain in 1747 at St-Michel d'Yamaska. Their son Jean-Baptiste St-Germain was a great-great-grandfather of Joseph Arthur Martin.