Brien is a Partner and is the Co-leader of Private Equity Practice at Sidley Austin, LLP. He is also recognized in Chambers USA for Private Equity: Buyouts in New York. Brien represents large cap and middle market private equity sponsors and other private capital investors and asset managers, as well as their portfolio companies, in connection with complex transactions including mergers, acquisitions, dispositions, financings, and general corporate matters. He has extensive experience in domestic and cross border leveraged buyouts, take-privates, carve-outs, distressed investments, special situations and structured equity investments and joint venture transactions.