Kathrine Belanger Tiffany was born in 1878 in Neillsville, Wisconsin, to Ferdinand and Margery (Johnston) Belanger. Kathrine was the second of three daughters. The family moved to North Dakota and purchased a quarter section in Morgan Township, Traill County, in 1884. Kathrine graduated from the University of North Dakota in 1902 with a bachelor's degree in English. She then taught English in Valley City, North Dakota, and became principal of Lidgerwood High School, all the while continuing work on a master's degree in English, which she received in 1908. Over the years, Kathrine continued her graduate studies at the University of Chicago, University of Washington, Harvard, and Northwestern, accumulating the equivalent of three years of graduate work in various disciplines she found interesting.

Kathrine married Neil Carnot Macdonald, superintendent of Lidgerwood schools, in 1904. Macdonald served in that same capacity in Mandan in 1910, was appointed state inspector of elementary schools in 1911, and was elected North Dakota Superintendent of Public Instruction in 1916. He and Kathrine pushed for rural school consolidation. Macdonald was defeated in 1918, and the Macdonalds left North Dakota in 1921 for the Pacific Northwest. Neil Macdonald died unexpectedly in 1923 of uremic poisoning while en route to accept a deanship at Seattle Pacific College.

Kathrine taught English at Seattle Pacific College, followed by English and Rhetoric at Whitworth College in Spokane. She married Orrin E. Tiffany, who had been President at Seattle Pacific and Dean at Whitworth. Orrin turned down the presidency of Whitworth College, and he and Kathrine joined the faculty of Wheaton College in Illinois.  Kathrine taught English for eighteen years at Wheaton and was considered an outstanding teacher. Orrin Tiffany died in 1950. In his memory, Kathrine established the Tiffany Lectureship.

Even after leaving North Dakota, Kathrine maintained a very close relationship with and interest in the University of North Dakota. She became a charter member in the Fellows of the University, endowed the Chester Fritz East Asian Room, and donated items to it and to a Graduate Study Center in the Library. Kathrine also encouraged her nephew, Chester Fritz, to establish the Chester Fritz Scholarships, the Chester Fritz Professorships, and to provide one million dollars for the building of the Chester Fritz Library, dedicated in 1961. Fritz donated another million for the Chester Fritz Auditorium, which opened in 1972. Kathrine was persuaded to accept UND's highest alumni honor, the Sioux Award, in 1964, although she declined to be honored at the 75^th anniversary celebration in 1958 with an honorary doctorate in recognition of achievement of success and evidence of quality performance in teaching.

Kathrine B. Tiffany died April 18, 1978, at the Presbyterian Retirement Home in Quarryville, Pennsylvania.