He continued his studies in Leipzig, entering the university there, all the while composing works on commission. In Leipzig he founded a “Collegium Musicum”, which was arguably the progenitor of the Gewandhausorchester, the world’s oldest orchestra. After graduating, he traveled around Germany, working in clerical jobs while continuing his composition, finally becoming Kapellmeister in Anhalt-Zerbst in 1722. The same year he famously turned down the position of Cantor at St. Thomas Church in Leipzig – this would soon be Johann Sebastian Bach’s job.
In 1736, his son, the composer Carl Friedrich Christian Fasch, was born. Fasch fils was a close associate of Carl Philipp Emanuel Bach. Fasch remained in Zerbst for the rest of his life, dying there in 1758.
Much of his music has been lost, as none of it was printed during his lifetime, and it survived only in manuscript form (J.S. Bach in fact copied out five orchestral suites composed by Fasch). He composed numerous sacred and secular works; his orchestral music is marked by unusual scorings, progressive for their time, which pointed the way to the early Classical style of Gluck, Haydn, and Mozart.