Porrino joined Lowenstein Sandler as a partner in 2004, and served as vice chair of the firm's litigation department, focusing his practice on criminal and civil trials.

After serving as the 60th Attorney General of New Jersey, Porrino returned to Lowenstein Sandler in 2018 as a partner and chair of the firm's litigation department.

He is a crisis manager, having represented numerous private and public companies and individuals in alleged scandals, including Governor Christie during the "Bridgegate" scandal, and currently represents individuals and businesses of all sizes in civil, criminal, and regulatory matters involving securities, consumer fraud, banking, insurance, tax, antitrust, real estate, and the environment.

The state legislative panel was to be tasked with looking into certain hiring practices and an alleged sexual assault that occurred during the governor's campaign.

Porrino served as Director of the Division of Law in the Attorney General's Office[4] from February 2012 to January 2014, overseeing a team of 800 state employees, 500 of whom were lawyers.

On his first day as Chief Counsel, the Fort Lee lane closure scandal, known as "Bridgegate", broke in the news media.

Using a validated risk assessment tool, dangerous and high-risk defendants are now held in custody and can no longer “buy” their way out of jail pending trial.

In a case that received national attention, Porrino led a civil rights action against the Township of Mahwah wherein it was alleged that local officials engaged in a pattern of discrimination to exclude Orthodox Jews.

The department designed and mandated the first-ever statewide continuing education curriculum to train police on de-escalation, cultural awareness, and implicit bias.