German composer. Son of Johann Tobias Krebs, an organist who was a student of Johann Gottfried Walther and J. S. Bach in about 1714. Received early lessons from his father; entered the Leipzig Thomasschule in 1726, where he studied lute, violin, and keyboard, and was a private pupil of J. S. Bach, whom he served also as a copyist. Bach gave him a glowing recommendation in 1735; he attended Leipzig University in 1735-37, also playing in Bach's collegium musicum. Served as organist at the Marienkirche, Zwickau (1737-44), at Zeitz (1744-56; he applied unsuccessfully for Bach's Thomaskantor post during this time), and at the court of Altenburg-Gotha (1756 to his death). A renowned organist; his output includes keyboard works, sinfonias, and church and chamber music.