From 2002 until 2005, he was a member of the governing board of the Competition Authority of Ireland, where he held the criminal investigations and merger review portfolios.

Calvani practiced antitrust law with Freshfields Bruckhaus Deringer, resident in its Washington, D.C., office from 2005 until his retirement in April 2019.

He is a life member of the American Law Institute, the Judicial Conference for the Sixth Circuit Court of Appeals and serves on the advisory boards of the Antitrust Bulletin, Oxford Journal of Antitrust Enforcement and Dublin University Law Journal, and has been a member of the Administrative Conference of the United States.

Calvani has served as a Non-Governmental Advisor (NGA)for the United States Department of Justice Antitrust Division and the United States Federal Trade Commission to the International Competition Network (ICN) since 2005, and has provided technical assistance to competition enforcement agencies in Africa, Asia and Latin America.

He was previously married to Mary Virginia Anderson of Mill Valley, California and Judith Tbompson of Birmingham, Alabama.