[8] Following her graduation from Louisiana State University Law School, Berrigan was a staff attorney of Governor's Pardon, Parole and Rehabilitation Commission from 1977 to 1978.

[8] She was a frequent speaker in locally sponsored continuing legal education programs,[8] and she served as an adjunct professor at LSU and Loyola School of Law.

[7] She served as Chief Judge from 2001 to 2008[7] and assumed senior status on August 23, 2016, under President Obama, [9] though Trump got to name her successor due to the Republican-controlled Senate holding her seat open.

During her time as an active judge for the Eastern District of Louisiana, she was largely considered among the most liberal of those serving New Orleans.

[11] The case was based on allegations that Nagin had accepted over $500,000 in gifts in exchange for official favors, as well as committed tax and wire fraud[12][13] contrary to his promises when assuming office that he would reform the corrupt New Orleans City Hall.