Their music have been classified as post-hardcore, noise rock and math rock, but Shellac described themselves as a "minimalist rock trio".

Shellac recorded and performed infrequently due to their geographic separation (Albini lived in Chicago, as does Weston; Trainer lives in Minnesota) and the fact that all the members had day jobs (Albini was a recording engineer, as is Weston; Trainer managed a warehouse and tended bar).