From 1958 to 1970 he was the Permanent Representative of Luxembourg to the European Communities, later the European Union.
From 1970 to 1976 he was a member of the European Commission with responsibility for competition, under the presidencies of Franco Maria Malfatti, Sicco Mansholt and François-Xavier Ortoli.
His tenure saw the break-up of the sugar cartel.
From 1970 to 1973, he was also the Commissioner for regional policy and the budget.
A conference centre in Brussels is named after him, of which a Dutch journalist once asked, what Borschette had committed, to merit having such an ugly building named after him.
A street in Kirchberg in Luxembourg City is also named after him.