Clara Barton began public work as a teacher, helping establish a school at Bordentown, New Jersey, before moving into clerical employment at the United States Patent Office. These roles exposed restrictions placed on women in professional life. When the Civil War began, she collected supplies for soldiers and developed an independent system for taking assistance closer to the fighting. Her work depended on donations, transport, and negotiation with military authorities as well as personal care.

Barton went to battlefields including Antietam and Fredericksburg, bringing food, dressings, and other necessities to wounded men. She did not operate as a modern licensed nurse within a standardized hospital system; her contribution combined emergency care with the organization and delivery of supplies. After the war she directed an office seeking information about missing soldiers and helped identify graves at Andersonville. The work connected families with records of deaths and captivity that wartime administration had failed to resolve.

During travel in Europe she encountered the international Red Cross movement and worked in relief during the Franco-Prussian War. Returning to the United States, she campaigned for participation in the Geneva Convention and founded the American Red Cross in 1881. She helped extend its mission to natural disasters as well as war. Relief operations included the Johnstown flood, other floods and storms, and assistance during the Spanish-American War. Her home at Glen Echo became a headquarters as well as a residence, joining institutional work with daily operations.

Barton led the organization until 1904, when disputes over finances and centralized management brought her resignation. The change reflected the difficulties of moving from personal leadership to a larger accountable institution. She continued interests in first aid and relief before her death in 1912. Her career helped make organized civilian disaster response a lasting American institution. Its importance rests on practical systems of collection, transport, information, and assistance rather than only the image of an angel on the battlefield. She widened opportunities for women while also facing criticism of her own administration. The missing-soldier work and Red Cross campaigns show how direct experience of suffering could be converted into records and institutions intended to prevent people from being left without aid.