The Polyphonic Spree's ever-changing line-up consists of Tim's lead vocals accompanied by a choir, piano, synthesizers, guitar, bass, drums, percussion, flute, trumpet, trombone, violin, brass horns, harp and sometimes cello. Individual members and the number of musicians, however, vary, due to the flexibility necessary in traveling with such a large band. The songs are mainly originally written and composed by DeLaughter on piano or guitar.
A significant distinguishing visual feature of the band, and what people usually first notice upon seeing the group for the first time, is that they wear robes onstage. This often leads to the misconception that they are a religious cult, or somehow a "religious" (or, more specifically, Christian) band. Contrary to this presumption, the robes are worn, according to DeLaughter, because the stage presence of over twenty people in their normal dress would be overwhelming. It unifies the band, although different colors allow for an element of individuality.
- White robes with a coloured trim at the bottom were worn from the band's conception until 2004.
- Purely red robes were worn for a number of UK festival dates in 2003. In addition, these robes are worn annually for the Chirtmas set of the Polyphonic Spree Holiday Extravaganza, often coupled with Santa hats and reindeer antlers.
- "Technicolor" robes, which included many different hues, were worn for the Together We're Heavy tour from 2004 to early 2005. Tim's robe changed from green at the beginning of the tour to watermelon in the midst of the tour.
- The robes worn from 2005 onwards to May 2007 were sky blue with a red jagged wave across the midsection. When the band stand in a line they look like a sound wave or heart monitor.
- The white robes with the colored bottoms began to be worn again in June 2007, probably because of the lighter fabric.
- The Fragile Army tours in 2007 also brought a black military style jacket and pants uniform that is worn in the main set. The robes return in the encores.
The band have released three complete albums to date: The Beginning Stages Of... from 2000 to 2003; Together We're Heavy in 2004; and The Fragile Army in 2007. The Beginning Stages is actually a demo recorded at the band's inception in 2000, but has been released 4 further times in the US and the UK.
In 2005, Tim DeLaughter was commissioned by director Mike Mills to write a full score for the movie Thumbsucker. He worked with some members of the band to write and record the mostly instrumental score, which features three songs by Elliott Smith.
2006 brought the band to a new recording style. Hollywood Records was done with them, so they began recording without a label, eventually being picked up by TVT in the US and GUT in the UK. The band was split up in sections and recorded in different areas of the US. The Fragile Army was born and was released on June 19, 2007.