Born in Potsdam, Gaillard, who lost his father early, attended grammar school in Berlin and in 1829 became an apprentice in the Berlin bookshop of Carl August Challier (1813-1871).
[2] There, he supported the young Richard Wagner by name and sent him his drama Cola Rienzi for review in 1844.
[3][4] Wagner's opera Rienzi (1842) inspired Gaillard to write his drama of the same name.
He also wrote under the abbreviation "C. G." for the Signale für die musikalische Welt published in Leipzig.
In the last years of his life he worked as a city councillor and was involved in issues of emigration.