Born in Pforzheim, Förtig received his first piano lessons at the age of eight with Hedwig Fuchs and from the age of 11 onwards he received lessons in piano and music theory from Georg Mantel and Heinrich Casimir in Karlsruhe.
1951 saw the premiere of a composition for the Southwest German Chamber Orchestra Pforzheim; in the same concert he appeared as soloist in Beethoven's first piano concerto in C major.
After graduating from the Reuchlin Gymnasium in Pforzheim, he studied from 1953 to 1955 at the Musikhochschule Karlsruhe, where Josef Schelb was his piano and composition teacher.
In 1957 he continued his studies at the Freiburg Music Academy, where Carl Seemann (piano) and Wolfgang Fortner (composition) were his teachers.
From 1965 to 1967 he completed supplementary composition studies with Klaus Huber at the Basel Academy of Music.