[1] During World War II Keiser was drummer in various entertainment and jazz groups, among others, together with Lukas Cheese Burckhardt in his own orchestra César Roy.

On 18 April 1962 his satirical program "César Keiser: Solo Programm" on Theater am Hechtplatz at Limmatquai Zürich premiered, co-directed with Margrit Läubli.

Almost all programs premiered at the Theater am Hechtplatz, then Keiser and Läubli went on tour in Switzerland, and partly they gave guest performances in Germany and in the United States, in Washington and New York.

Among the longtime musical staff were René Gerber, Hans Moeckel, Werner Kruse, Bruno Spoerri, and later his other son Mathis Keiser.

In addition to these duo programs, in 1976 Keiser and Läubli directed the exhibition "1916–1976: 60 Jahre Theater in der Schweiz" in the Helmhaus gallery-museum in Zürich.

In the musical "Lueg uf zrugg Züri", he staged together with Läubli, alongside Elizabeth Quick, Noëmie Nadelmann, Ueli Beck, Ernst Stiefel and over eighty laymen actresses and actors, at the "Stadthof 11" theater in Zürich-Oerlikon.