Esther Clayson was born in Seabeck, Washington Territory on November 16, 1869. She became the second woman to graduate from the University of Oregon Medical School in 1894. Shortly thereafter, she married classmate Dr. Emil Pohl and began to establish her obstetrics and gynecology practice in Portland. In 1907, she was appointed Portland City Health Officer, the first woman to hold the post in a city of its size. A year later, her 8 year old son, Frederick, died of perforation of the bowels due to impure milk. This tragedy influenced her tenure as Health Officer, during which she installed the city's first school nurse, wrote its first milk ordinance, and established school inspections to ensure detection and prevention of disease. In 1911, her husband Emil contracted spinal meningitis and died in Fairbanks, Alaska. Despite these losses, Lovejoy's commitment to public health, particularly women's health, remained firm. When Esther left the Health Department, she became head of the Department of Obstetrics and Gynecology in the Portland medical group of Coffey, Sears, Jones, and Joyce. During this period, she married Portland businessman George Lovejoy. Dr. Lovejoy was an outspoken advocate for women, playing an active role in women's suffrage groups and running for Congress in 1920.

Dr. Lovejoy served with the Red Cross in Europe during World War I, where she developed a keen interest in medical relief work with refugees of war. She was appointed chair of the American Women's Hospital Service (AWHS) in 1919 and led the organization until her retirement in 1967. Founded by the Medical Women's National Association, the AWHS sought to advance the work of women in medicine and provide transnational medical relief. In this capacity, she traveled widely to alleviate suffering from war, disaster, famine, revolution, and poverty. Dr. Lovejoy also served as the first president of the Medical Women's International Association, which she helped found in 1919. Her leadership and service to these organizations is commemorated by various monuments erected in her honor: a bust of Dr. Lovejoy stands in the town square of Nikaia, Greece, and a mural with a portrait of Dr. Lovejoy is displayed in the Esther Pohl Lovejoy Hall at the Philippine Medical Women's Association building in Manila.

Dr. Lovejoy was also a prolific writer, publishing her first book, , in 1919. In it she described her relief work with the Red Cross during World War I. Her next book, , documented the complex work of the American Women's Hospitals Service. In 1939 she completed , a monumental task fulfilled by researching archives and searching in attics all over the world. She published her final book, , in 1957. This collection also contains her unpublished autobiography, .

Esther Pohl Lovejoy lived without extravagance and worked endless hours. In 1963, four years before her death, she traveled to Alaska, Tokyo, Hong Kong, and Manila. She revisited the University of Oregon Medical School where she had established the Pohl Memorial Scholarship Fund in memory of her first husband and son, saying that she was glad for "the chance to remind the trustees that one third of the scholarships should go to girls." Dr. Lovejoy died at 97 years of age and was buried at the Lone Fir Cemetery in 1967 after a long and successful career.