SmogSmog, at one point briefly renamed (Smog), is the musical alias of Bill Callahan, born in Silver Spring, Maryland. Callahan pioneered the lo-fi genre of underground rock, with homemade tape-albums recorded on four track tape recorders. Later he signed a record contract with the label Drag City.

Callahan started out as a highly experimental artist, utilizing sub-standard instruments and recording equipment. His reason for using the lo-fi approach was not so much an aesthetic choice, rather it came from his lack of knowledge of recording studios, and fear of giving up control to professional engineers.

His later work saw him overcoming his fear of studios and producers, and in this period he recorded two albums with the influential producer Jim O'Rourke and musicians from the circles around Drag City, as well as collaborating with the similar-minded Neil Hagerty.

His songs are based on simple, repetitive structures, strikingly characterized by his baritone vocal. His lyrics are often centered around themes of spiritual searching and the complexity of emotions, with the use of subtlety and dark irony in the classic sense. There is also a broad swathe of joy throughout Callahan's work. He is a keen storyteller using simple words to project large and deeply echoing tales.

Callahan's love life has been documented with vigor in numerous hipster publications, including his romantic relationship with Chan Marshall (Cat Power), who allegedly penned "To Be a Good Woman" in tribute to Callahan while referencing his song "To Be Of Use." It has been rumored as of late that Callahan is now involved with Drag City labelmate Joanna Newsom.

Callahan is widely seen as one of the important figures of American rock in the '90s. He currently resides in Austin, TX where he recorded his most recent album, A River Ain't Too Much to Love.