Peter Mills Mattoon, 84, who led Ballard Spahr with a decisive and unifying hand during a period of dramatic growth, died March 29 of injuries sustained in a fall. Under Mr. Mattoon's leadership in the 1980s and '90s, Ballard Spahr built upon its strength in Public Finance and Business and Finance and established itself as a force in Litigation and Real Estate.

Even as the Firm grew, Mr. Mattoon preached the importance of a "one-firm Firm," a principle of institutional loyalty that still guides the Firm and is perhaps his most enduring legacy. His goal as Chair, he said in one speech, "was a civilized and successful firm."

"Peter presided over a period of upheaval that might have mired the Firm in the misery of mediocrity," Ballard Chair Mark Stewart said. "His strong yet calming leadership, combined with the well-earned respect of his partners, took the Firm to new heights and success."

Tall and dignified, Mr. Mattoon was a man of few words, almost none about himself.  He projected the image of a strong, confident leader whose direction others would follow willingly.

"Peter had that character, that presence," said Robert McQuiston, a retired partner. "He was just so sound, so solid, so deliberative, and he cared about the culture of the Firm."

"He made us see the importance of working together," said partner John Langel, whom Mr. Mattoon hired, mentored in sports law, and eventually tapped to form the Firm's highly regarded labor and employment practice. "To Peter, 'one-firm Firm' did not mean complacency. I first heard from Peter the concept that we were falling behind if we were doing today what we did yesterday."

Partner Geoff Kahn remembers the Annual Meeting at which Mr. Mattoon introduced the one-firm Firm philosophy. "Although we initially thought it was a bit corny, it stuck with many of us because it captured perfectly who we were, and wanted to be, as a firm," he said. "Peter wasn't loud or flashy, but led with uncommon wisdom and intelligence – and a devilish sense of humor – for almost two decades, which is remarkable in itself."

During Mr. Mattoon's term as Chair, the Firm broadened its geographic reach beyond Center City Philadelphia and Washington, D.C., opening offices in Denver, Salt Lake City, and Baltimore. The Firm focused on finding the very best talent and Mr. Mattoon was adept at attracting top lawyers from competitor firms at a time when such lateral hiring was not yet commonplace. Some of those hires were transformative and helped to distinguish Ballard Spahr.

Michael Sklaroff was among those who joined Ballard Spahr during the Mattoon era, bringing a group from Schnader Harrison Segal & Lewis that found a receptive environment in which to build a real estate practice.

"Peter enriched the Firm's DNA with lawyers who had achieved success in other firms, and who wanted to enjoy the Ballard culture of civility, cooperation, and teamwork," Mr. Sklaroff said. "It was the rich diversity of experiences and backgrounds that energized the Firm in those days and still does."

Mr. Mattoon embodied civility in the practice of law, which made him the perfect advocate for lateral recruitment. He also appreciated the risks and emotion involved for lawyers who left their professional homes to come to Ballard.

"Peter once told me that there would be times when I would think this was the best professional decision I ever made and times when I would think it was the worst," said Mr. Sklaroff, whose move to Ballard in 1985 was preceded by two years of discussions with Mr. Mattoon. "Actually, it was and is for me the best professional decision I could ever have made."

Before he was its Chair, Mr. Mattoon was Ballard Spahr's hiring partner and some of the law students he recruited went on, decades later, to hold leadership positions at the Firm. His advice to associates was to learn, as he had, by observing the partners.

In his legal practice, Mr. Mattoon was a trusted adviser to some of Philadelphia's most prominent citizens, including Marvin Wachman and the institution he led, Temple University, and Fitz Eugene Dixon Jr., an influential philanthropist and civic leader who owned the 76ers and the Philadelphia Wings lacrosse team and a portion of the Phillies, Eagles, and Flyers. When Mr. Dixon decided he wanted Julius Erving for the 76ers, it was Mr. Mattoon who helped close the deal that brought "Dr. J" to Philadelphia.

As counselor to Mr. Dixon, Mr. Mattoon became involved in a wide range of legal areas well beyond estates law, his field of concentration. He was an elegant writer and respected litigator, "a renaissance lawyer," as Mr. McQuiston described him.

Mr. Mattoon's thoughtful approach to the practice of law was never more apparent than when he accompanied Mr. Dixon to meetings of the NBA owners in the late '70s and early '80s. The NBA was at a crossroads and meetings were tense. Mr. Mattoon would listen intently and rarely speak, but when he did have something to say, he commanded the attention of everyone in the room. Those meetings were led by David Stern, who was then general counsel of the league and went on to be its commissioner. Years later when they ran into each other at Madison Square Garden, Mr. Stern told Mr. Langel that Peter Mattoon was one of the finest lawyers and most decent people with whom he had ever worked.

In his management of client relationships, and in the governance of a law firm that was in the throes of growth and change, Mr. Mattoon was politically astute and resolute under challenging circumstances. When a change in leadership at an important client nearly led to another firm being named primary outside counsel, he worked patiently, tirelessly, and successfully to hold onto the client.

"On leadership, Peter was generations ahead of his time," Mr. Stewart said. "His wisdom is now routinely packaged by consultants as a newly discovered key for successful law firm management." The principles Mr. Mattoon applied during his years as Chair, and which became unifying ideals for the Firm, were the absolute necessity to evolve as an institution and as individual lawyers, and the critical importance of understanding a client’s needs and goals.

Mr. Mattoon joined Ballard Spahr in 1959 after his graduation, cum laude, from Harvard Law School. He received his A.B. in 1953 from Dartmouth College, magna cum laude. In between, Mr. Mattoon served for three years as a U.S. Navy officer in the Pacific Fleet. As a student, he held a variety of summer and temporary jobs, from bellboy to mail carrier to cutlery salesman. Born in Bryn Mawr, Pennsylvania, and raised in nearby Bala Cynwyd and Penn Valley, he was educated at The Episcopal Academy, whose board he later chaired.

His civic involvement showed his breadth and the esteem in which he was held. Mr. Mattoon served on the boards of important regional institutions including PNC Bank's Regional Advisory Board, Thomas Jefferson University, the Philadelphia 76ers, Provident National Bank, Widener University and the Widener University School of Law, and the Greater Philadelphia Chamber of Commerce.

As Chair of Ballard Spahr, Mr. Mattoon was instrumental in the Firm's move in 1991 to the Mellon Bank Center, then a distinctive new addition to the city skyline. When a private club, The Pyramid Club, opened on the building's top floor, Mr. Mattoon was chosen to lead its board of governors.

Mr. Mattoon stepped down on the last day of 1997 after more than 16 years as the Chair of Ballard Spahr. That fall, his partners had feted him with a black tie celebration at the Independence Seaport Museum. They later named the Firm's largest conference room for him, the first time a partner had been honored in that way. He retired as a partner of the Firm in 2001 and served as Senior Counsel through 2010. Even after he ceased active practice, Mr. Mattoon visited the Firm regularly, attending events and maintaining close relationships.

Mr. Mattoon and his wife, Joan, to whom he was married for more than 60 years lived on the Main Line and then in Lafayette Hill. At the time of his death, he was a resident of The Hill at Whitemarsh. The couple traveled extensively, often as passengers on small cruise ships. With old friends from the Firm, Mr. Mattoon took a class each semester at University of Pennsylvania, most recently studying the history of Europe.

In 1998, the American Jewish Committee's Philadelphia Chapter honored Mr. Mattoon with the Judge Learned Hand Award. In his acceptance speech, he drew on Judge Hand's observations in reflecting on his own life and career. "I have experienced, when practicing and while chairman of Ballard Spahr, 'the drudgery, senseless bickerings, stupid obstinacies' and I certainly have thought repeatedly that 'I may be mistaken'. But I have also had the pleasure first of my practice growing and changing from being an estates lawyer to representing the 76ers and representing Temple University. Then a new opportunity as chairman, where my goal was a civilized and successful firm. And out of the murk in both practice and as chairman I have had the pleasure of sometimes seeing patterns appear which I had something to do with.

"An added and greater pleasure are Joanie's and my children, who appear civilized and successful.

"But I remain a skeptic, and cannot know what contribution I have made to all of this, but I have tried to do a workmanlike job and tonight I am happy to shine in the reflection of my family and Ballard Spahr."

Mr. Mattoon is survived by his wife; his daughter, Pamela Zisselman; sons Stephen, Peter, and Philip Mattoon; and 10 grandchildren.

Services will be at 2 p.m. on Saturday, April 16, at The Presbyterian Church of Chestnut Hill, 8855 Germantown Avenue, Philadelphia. Memorial donations: The Educational Grant Committee for Part Time Employees at the Hill at Whitemarsh, 4000 Fox Hound Drive, Lafayette Hill, Pa. 19444.