Sieff has worked with many bands and artists including Wasted Youth, The Bad Plus, Herbie Hancock, Alexis Korner, Hugh Masekela, Big Country, Angelique Kidjo, Wynton Marsalis, Branford Marsalis, Denys Baptiste, Jazz Jamaica, Albert Collins, Keb' Mo', Spitting Image, Edoardo Bennato, Matumbi, Peter White and Clare Teal.