The group, led by metals tycoon and executive chairman Sanjeev Gupta, has a host of interests in Scotland such as the Liberty Steel plant in Dalzell, Motherwell, and tidal power firm Simec Atlantis Energy.
Barrell will take up the new role on 1 January, after joining GFG Alliance as the global head of integration and performance earlier this year.
Initially, his focus will be on bringing GFG Alliance’s Liberty Steel businesses across the globe into one consolidated Liberty Steel Group.
Gupta said: “The creation of a global COO role allows a sharper focus across the group on operational improvements and formalises the work Neil and his team are already leading on integration and performance.”
Barrell joined GFG Alliance in June from accountant Grant Thornton, where he was a senior partner as head of UK manufacturing and industrials, and the firm’s global automotive leader.
He said: “Working towards the consolidation of Liberty Steel Group and ensuring we are making strides to reach our 2030 target of being carbon neutral will be among my initial priorities.”