Sachs conducted the Liederkranz Society from 1868 to 1872, and in 1871 was appointed a teacher of harmony at the Royal Music School. From 1869 until 1873 he conducted a male choral society at Munich, and he was the founder and conductor of the Tonkunstlerverein.
As a music theorist he held original opinions on many points. Among his numerous compositions, of which the greater part remain unpublished, are symphonies; symphonic poems; an opera, Palestrina, which was performed at Ratisbon in 1886; a ballad, Das Thal des Espingo, for chorus and orchestra; a paternoster; and one work of gigantic dimensions, entitled Kains Schuld und ihre Sühne (Cain, His Sin and Atonement), the production of which was intended to fill seven evenings. He also composed many songs and much piano music.