After service as a captain in World War I, he joined one of the predecessor firms to Milbank, Tweed, Hadley & McCloy, where he remained as a partner the remainder of his life.
Legal aid, he wrote, was "operation equal justice," "an obligation of the bar," and essential to secure the success of the adversary system.
To rejuvenate the staid organization, he brought in younger lawyers, established a bulletin, reorganized committees that issued reports, and created the position of executive secretary.
He took a light, subtle approach, usually talking around the matter at hand so as to envelop the object of his attention; only occasionally did he take a direct part in the proceedings over which he smoothly presided.
Starting in 1947, Tweed was chairman of the ALI - American Bar Association (ABA) joint committee on continuing legal education.
He wrote articles, spoke to lawyers' groups, buttonholed bar leaders, and organized conferences.
In his term as interim president, he is credited with saving the college from bankruptcy by increasing the number of students.
[1] He also served as an overseer of Harvard University from 1950 to 1956, and from 1951 to 1967 he was a trustee of the Cooper Union Center for the Advancement of Science and Art in New York City.
In 1963, at the request of US President John F. Kennedy, Tweed became co-chairman of the Lawyers' Committee for Civil Rights Under Law, a position that he held for two years.
Tweed believed that lawyers' training to define complicated issues enabled them to play a special role outside the practice of law: "Even if he contributes nothing more than a sense of orderliness and an ability to organize thought and to pose the right questions, the lawyer will have pulled his weight in the boat."
Of his year as president of Sarah Lawrence College, he wrote, "I think that I did manage to bring to the faculty an organization and an understanding of democratic procedures which no one but a lawyer could have done."
See his chapter, "One Lawyer's Life," in Albert Love and James Saxon Childers, eds., Listen to Leaders in Law (1963).
George Martin, Causes and Conflicts (1970), deals with Tweed's activities in the New York City bar association.