Knight is senior research investigator at Imperial College where, until 2010, he was deputy rector (research). He was knighted in 2005 for his work in optical physics. Knight was the 2004 president of the Optical Society of America and 2011-2013 president of the Institute of Physics. He is editor of Contemporary Physics, chair of the UK National Quantum Technology Programme strategy advisory board, chairs the Quantum Metrology Institute at the National Physical Laboratory, was until 2010 chair of the UK Defence Scientific Advisory Council and remains a UK government science adviser. His research centres on quantum optics and quantum technology. He has won the Thomas Young Medal and the Glazebrook Medal of the Institute of Physics, the Ives Medal and the Walther Medal and Prize of the OSA, the Royal Medal of the Royal Society and the Faraday Prize of the IET.