Schreiber is one of the researchers, or "elves", for the television panel game QI. On 30 July 2009, Schreiber hosted an unnamed radio pilot which was performed in a manner similar to a radio breakfast show. He has contributed to a number of books including The Naked Jape by Jimmy Carr and the QI spinoffs The Book of General Ignorance and G Annual. Schreiber also appears as a panellist and presenter on the BBC panel show No Such Thing as the News.
After five seasons working for QI, Schreiber headed up an online start-up called ComedyBox at Warner. "The whole idea of ComedyBox was to fund people who wouldn’t be given money by TV stations, to make comedy sketches." There, Schreiber executive produced Ken Russell's short Christmas film A Kitten for Hitler, and Flight of the Conchords star Rhys Darby's ComedyBox clips and stand-up DVD: Imagine That!
As a stand-up comedian, Schreiber has toured with FolkFace from Radio 1's Chris Moyles Show and is a regular panelist on the E4 show Dirty Digest.
In 2016 he hosted No Such Thing as the News alongside James Harkin, Andrew Hunter Murray and Anna Ptaszynski on BBC Two. It is a television spin-off of the No Such Thing as a Fish podcast, in which the four QI Elves discuss their favourite facts that they have learned that week.
^Bob Pipe (17 March 2014). "Comedy Box (playlist)". Retrieved 12 November 2016 – via youtube.com. I was in-house producer/director at Warner's ComedyBox.tv from 2007-2009. We later became MySpace Comedy. I shot, edited, produced and/or directed hundreds of comedy sketches. Here's a few of them