Levi played a pivotal role in the transformation of picture framing in the decades following the Second World War and created a wide range of frames based on historic styles for public and private patrons, including a number of the greatest art collections of Europe and North America.
Whilst interned he became friendly with others in the same situation, including Johannes Wilde (later deputy director of the Courtauld Institute), Max Perutz (the molecular biologist who was awarded the Nobel Prize for Chemistry in 1962) and the mathematician Sir Hermann Bondi.
The intellectual approach adopted by Levi was unusual at that time, given that the Modern movement was increasingly dominating public museums and galleries (for example Franco Albini's 1950 decision to remove the frames from the Old Master paintings in the Palazzo Bianco and display them against white walls).
It was Levi who first reconstructed the machine needed to recreate the black ripple moulding frames for reframing of Dutch 17th-century paintings.
One of Levi's greatest successes after his retirement, and in collaboration with William Adair, was the identification of the 11 paintings needed to reassemble Filippo Mazzola’s polyptych that formed the altarpiece in the church of S Maria delle Grazie at Cortemaggiore.