Kayhan Kalhor has a wide range of musical influences, uses several musical instruments, and crosses cultural borders with his work, but at his center he is an intense player of the Iranian violin.
In his playing Kalhor often pins Iranian classical music structures to the rich folk modes and melodies of the Kurdish tradition of Iran.

Kalhor has composed works for and played alongside the famous Iranian vocalists Mohammad Reza Shajarian and Shahram Nazeri. He has also composed and performed with the Indian sitar player Shujaat Husain Khan and Indian tabla player Swapan Chaudhuri in the group Ghazal.

Kalhor's 2004 album In the mirror of the Sky was a joint venture with the Kurdish Iranian lute player Ali Akbar Moradi. His 2006 album The Wind is a collaboration with the Turkish baglama virtuoso Erdal Erzincan, with both Turkish and Persian pieces performed.

At other times Kalhor has collaborated with Yo-Yo Ma's Silk Road Project Ensemble in the USA and the Kronos Quartet.

Kalhor now resides in USA and has been commercially successful in USA over the past decade. Two of his works were nominated for Grammy Awards in 2004.

In 2010 Kalhor composed "I was there", which was based "on a melody attributed to Ziryab, a ninth-century Persian Kurdish musician", for a Maya Beiser concert. This piece was performed by Kalhor alongside Maya Beiser, the renowned cellist Bassam Saba, an oud player, and two percussionists, Glen Velez and Matt Kilmer.