McLean, who will retain his role with Gaucho, will spearhead CAU's expansion, which includes plans to open another six restaurants in the UK this year.
The steak restaurant group, which opened its first UK site in Guildford last July, has secured a site in Cambridge for its next restaurant and plans to open another five in the next 18 months.
"I look forward to continuing to work with the operational and creative teams as we build the brand in the UK," said McLean.
CAU, which stands for Carne Argentina Unica, opened its first branch in Amsterdam. Like its sister restaurant Gaucho, its focus is steak, but delivered in a more casual setting.