In the last phase of World War II, Geisler was drafted into the German Air Force, where he worked on the combat aircraft Heinkel He 162.

With the help of a fellow prisoner, Geisler built an electric guitar and learned as a self-taught player.

In addition, while appearing with the Wende band in the Hamburg night club "Tarantella," Geisler met Freddy Quinn, with whom he developed a long-term recording relationship.

In addition to Polydor, he also worked for other record companies and accompanied other singers like Evelyn Künneke, Greetje Kauffeld, Friedel Hensch, Esther and Abi Ofarim and Hildegard Knef.

For several years Geisler served as Chairman of the German Composers' Association and the executive board of GEMA.

In the spring of 2010, he was shown on the liner for Helen Schneider Swing CD – a tribute to Bert Kaempfert – where he participated as bassist.

In his later years, Geisler used a compact and lightweight guitar amplifier, specially selected for its sonic characteristics.