In 1942 Professor Friedrich Paneth was recruiting young chemists for the nuclear energy project. Wilkinson joined and was sent out to Canada, where he stayed in Montreal and later Chalk River Laboratories until he could leave in 1946. For the next four years he worked with Professor Glenn T. Seaborg at University of California, Berkeley, mostly on nuclear taxonomy. He then became a research associate at the Massachusetts Institute of Technology and began to return to his first interest as a student – transition metal complexes of ligands such as carbon monoxide and olefins.
He was at Harvard University from September 1951 until he returned to England in December 1955, with a sabbatical break of nine months in Copenhagen. At Harvard, he still did some nuclear work on excitation functions for protons in cobalt, but had already begun to work on olefin complexes.
In June 1955 he was appointed to the chair of Inorganic Chemistry at Imperial College London, and from then on worked almost entirely on the complexes of transition metals.
Wilkinson is well known for his popularisation of the use of Wilkinsons catalyst RhCl(PPh) in catalytic hydrogenation, and for the discovery of the structure of ferrocene. Wilkinsons catalyst is used industrially in the hydrogenation of alkenes to alkanes.
He supervised PhD students and postdoctoral researchers including John A. Osborn, Alan Davison and Malcolm Green.