He served in that capacity for ten years during which time he was active on a wide variety of state and national issues.

In December 1992 he was named as special attorney general to investigate misconduct allegations on the Pennsylvania Supreme Court.

In that capacity, he has commented on a wide range of trials from the celebrated cases of the early 1990s to the recent military tribunals in Guantanamo Bay.

Tierney may be best known as one of the key strategists in the state cases against the tobacco industry in reclaiming Medicaid payments paid out for tobacco-related disease.

[9] Tierney also has advised officials in Eastern Europe's emerging democracies, has supervised national elections in Bulgaria, Cameroon, Croatia and Albania, and was special counsel in the investigation of alleged corruption within the Pennsylvania Supreme Court.