Jonathan Kestenbaum is a member of the House of Lords, as well as a Director of JP Morgan Japanese Investment Trust, a Director of Windmill Hill Asset Management, and of Five Arrows Limited. He was previously the Chief Operating Officer of RIT Capital Partners plc.

Jonathan studied at the London School of Economics and Cambridge University and whilst a student was Secretary of the Bnei Akiva youth movement. In 1985 after graduating, he lived in Jerusalem where he studied at The Hebrew University of Jerusalem.  As a dual national at the time, he was conscripted into the Army. Based on his experiences, he published his diaries which were covered during the 1980s in the international press including The New York Times.  Kestenbaum returned to the UK in 1991 and took up his position as Chief Executive of the Office of Chief Rabbi Lord Sacks. He was then appointed CEO of the UJIA. Thereafter he became Chief of Staff to Sir Ronald Cohen, Chairman of Apax Partners. He was founding CEO of The Portland Trust, an organisation which works for peaceful reconciliation between Palestinians and Israelis. As CEO of The Portland Trust, Jonathan led dialogue to help resolve the Palestinian Israeli conflict and he also worked on economic co-operation between Palestinians and Israelis.

Thereafter he became Chief Executive of NESTA, the National Endowment for Science, Technology and the Arts, and subsequently joined RIT Capital Partners plc.

Lord Kestenbaum is a trustee of a number of charitable foundations, including the Jewish Leadership Council, having previously served as a Board member of the Royal Shakespeare Company. For five years he was a non-executive Director of the Government's Technology Strategy Board. Jonathan has previously served in various other non-executive roles including as non-executive director of BICOM, a Trustee of Teach First, and a Board member of Pershing Square Holdings plc. He chaired the Board of Directors of The Capital Holdings Funds (EDR Group) and he also chaired GVQ Asset Management.

Jonathan Kestenbaum was Chancellor of The University of Plymouth for thirteen years from 2013 until the end of his term of office in 2026. He was awarded an Honorary Doctorate in Technology from the University of Plymouth, an Honorary Fellowship from the Royal College of Art, and he was previously a tutor at the Cass Business School.

Appointed to the House of Lords in January 2011, Lord Jonathan Kestenbaum is no longer a dual national, he retains only British citizenship, and speaks in the Lords on education, innovation and economic policy.