Esther Hamilton was born in Hemet, California on Christmas Day, 1910, and graduated in 1928 from Hemet High School. She attended Riverside City College, and then the University of California, Berkeley. Her grandparents had moved to Southern California in the boom of 1887; her grandfather, Isaac Martin, was an early citrus grower in the small town of Highgrove, California. Her father, Charles Hamilton, was the first city clerk of the newly-formed City of Hemet, as well as an important grower of citrus in its early days in the area. In later years he was a fruit buyer.

At the age of 19, she married Leo J. Klotz, Ph.D., a researcher at the California Citrus Experiment Station and later a professor of plant pathology at the University of California, Riverside. Esther became interested in local history and beacme an avid and meticulous researcher and writer in her own right. She collected data on both Riverside City and County, as well as other Southern California cities, eventually resulting in several books. In 1972, she wrote Riverside and the Day the Bank Broke: A History of the City, 1890-1907, which chronicled the scandal leading to the downfall of the Orange Growers Bank. Her love of art, history, and the Mission Inn led her to publish The Mission Inn: Its History and Artifacts in 1981. In 1985, she collaborated with Joan H. Hall on a book documenting historic homes in Riverside,California, Adobes, Bungalows and Mansions of Riverside, California, which quickly sold out. A revised edition was later published by Hall. Klotz, Hall, and historian/author Harry Lawton also collaborated on a pamphlet in 1989, called "History of Citrus in the Riverside Area."

Passionate about the preservation of the area’s historic buildings and resources, she served on many boards. During the 1960s and 1970s she served as a founding member and chair of the Friends of the Mission Inn; as a member of the Riverside Pioneer Historical Society of Southern California (later renamed the Riverside Historical Society); the Riverside County Historical Commission; the Mission Inn Artifacts Committee; and the Friends of the Library of the University of California, Riverside. She also served as an advisor to the Jensen-Alvarado Ranch Associates and was a founding member in 1963 of the Riverside Museum Associates, serving as co-editor of its newsletter: the Report of the Riverside Museum Associates. After helping persuade the City of Riverside to form a special civic board devoted to the preservation of historic resources, she was appointed by the city council to act as the first chair of the resulting Cultural Heritage Board. She was an active member of several other local historical societies, most notably, The Old Riverside Foundation. She was named Riverside County Historian of the Year in 1983.

Esther H. Klotz died on August 2, 2000 at 89 years of age and is interred at Riverside’s historic Evergreen Mausoleum. She was survived by a son, Jerome; a daughter, Eunice Riemer; and several grandchildren.