Leadership is changing at one of New Jersey’s top law firms.

As of Jan. 1, Roseland-based firm Chiesa Shahinian & Giantomasi PC (CSG Law) announced Marie Mathews as managing member.

In the new role, Mathews will oversee the firm’s 200 attorneys and 150 other professionals. The team is assigned to the firm’s headquarters as well as its rapidly growing location in midtown Manhattan.

Mathews previously served in a variety of management positions at CSG Law, including as practice group leader of the litigation group and deputy general counsel to the firm. Her background also includes representing an array of clients in complex commercial litigation matters throughout the region.

Outside of the firm, Mathews serves as the president of the Greater Newark Holiday Fund. The charity has contributed more than $12 million over the years toward the betterment of thousands of families across the state.

Commenting on her new role, Mathews said, “I am looking forward to leading the firm through the exciting new opportunities on the horizon, as we continue to grow and build upon our past successes.”

Jeff Chiesa, co-chair of the executive committee, added, “I have worked closely with Marie over the years, witnessing first-hand her ability to build consensus, analyze issues and lead effectively. We look forward to her leadership as we continue to build and grow the firm.”

Making the transition

Mathews succeeds Patricia Costello, who held the post since 2022. During her tenure, Costello shepherded the organization through a variety of milestones, including the post-pandemic return to office, transitioning to a new headquarters at 105 Eisenhower Parkway in Roseland and modernizing many practices and policies, CSG law said.

Costello is also credited with continued smart growth at the firm in both revenue and headcount.

According to CSG Law, Costello will continue a leadership role by serving on the executive committee, the firm said.

Costello reflected on the change, saying, “Serving as managing member of the firm at this pivotal time in its history has been a tremendous honor. CSG is a special place and I look forward to contributing to its vision by serving on the executive committee.”

Francis Giantomasi, co-chair of the executive committee, thanked Costello “for her wisdom the steadiness of her leadership through the past three years. He continued, “We continue to look to the future and believe Marie will be an excellent leader to help continue our growth trajectory.”