Gruen's final legacy to Australian economics is probably his two sons. Dr David Gruen has forged a successful career as a professional economist at the Reserve Bank of Australia and then as a senior official at the Federal Treasury, where he headed the Macroeconomic Group. Dr Nicholas Gruen was an architect in the 1980s of the widely admired Button Car Plan – a plan for the transition of Australia's car industry to a regime of lower tariffs and higher export orientation – and has since advised the Business Council of Australia and the Productivity Commission as well as authoring reports for the Committee for Economic Development of Australia.