Mortimer M. Caplin was an American tax lawyer, educator and public servant whose career bridged private practice, government service and teaching. Born in New York City and associated with the state of New York, Caplin rose to national prominence in the early 1960s when he worked on federal tax policy and served in government roles. He was a founding member of the Washington firm Caplin & Drysdale, Chartered, and remained active in legal circles for many decades. He marked his 100th birthday in July 2016 and died at age 103 in Chevy Chase, Maryland.

Public service and federal appointment

Caplin served on President John F. Kennedy’s Task Force on Taxation, a group convened to review tax law and advise on reform during a period of economic growth and evolving fiscal policy. In January 1961 he was appointed Commissioner of Internal Revenue, becoming the head of the agency responsible for administering the federal tax system. In that role he represented the Internal Revenue Service in dealings with Congress, the executive branch and the public, and participated in efforts to improve taxpayer service and agency operations typical of the era.

Before and after his government service Caplin practiced tax law in private practice. He helped establish Caplin & Drysdale, a firm that became known for work in tax, estates and corporate matters. Throughout his career he combined practice with instruction, bringing practical experience into academic and professional settings. He lectured and mentored younger lawyers, sharing insights about tax administration, compliance and litigation. His combination of classroom attention and hands-on practice was a noted part of his professional identity.

Legacy and recognition

Caplin’s life is often cited as an example of a legal career that integrated public service, private practice and education. Observers note three principal aspects of his legacy: public administration at the helm of an important federal agency in the early 1960s; the founding and cultivation of a law firm with a sustained focus on tax and related specialties; and a long record of teaching and mentorship that influenced subsequent generations of tax professionals. His longevity made him a living link to mid‑20th century developments in U.S. tax law.

  • Public administration: Leadership of the Internal Revenue Service during a period of policy review and administrative change.
  • Law firm founder: Co‑founder of Caplin & Drysdale, with a continued emphasis on tax, estate and corporate practice.
  • Educator and mentor: Longstanding commitment to legal education and guidance for young attorneys.

For readers seeking primary documents or more detailed accounts of Caplin’s work, institutional archives, legal histories and firm profiles provide further information about his roles and writings. His career illustrates how expertise in tax law can be exercised across government, private practice and academic contexts.