Theodore Marten Rehder was born January 27, 1908, in Lincoln, Iowa. His parents were Theodore Peter Rehder (1873-1956) and Martha May (Martens) Rehder (1876-1946). In 1870, the Rehder family became established in Tama County, Iowa, in the small town of Berlin, which boasted a large German-immigrant population. Theodore P. Rehder was a cashier at the German Savings Bank (later named Lincoln Savings Bank) when it opened on September 4, 1902 and his father served on the first board of directors. T. P. Rehder also worked in real estate, farm loans, and insurance, as well as service to the town's administration. Berlin was renamed Lincoln after the outbreak of World War I. Theodore M. Rehder graduated from West Waterloo High School in 1926, where he served as president of Dramatic Club. As a senior, he helped his school place first in the Northeastern Iowa Declamatory (rhetoric) contest, with his contribution of "A Simple Case of the Grip," in the humor category.

For several years during the mid-1920s, Rehder sought summer work in Colorado. Like his father, Rehder enjoyed camping and fishing in the American Southwest. His interest was sufficient while attending West Waterloo High School that he collected information on forestry course requirements at Iowa State College of Agriculture and Mechanic Arts, in Ames, Iowa.

Rehder moved to Iowa City to attend the State University of Iowa, and initially took a job at Smith's Cafe, located at 11 South Dubuque Street. In October 1926, Rehder worked part time in the Iowa Memorial Union Dining Services. In December 1927, Rehder worked as desk clerk in the Iowa Union for director Rufus H. Fitzgerald, who also asked him to create a tour of the University. Rehder wrote to his parents that this work for Fitzgerald was "the first time that I have gotten paid for just thinking and planning." During the summer in 1928, Rehder sold Procter & Gamble soap door-to-door in St. Louis, Missouri, while living at the YMCA.

On May 25, 1929, Rehder was named assistant manager of the Union Dining Services, working full time in that capacity. On August 29, 1929, Rehder was named manager of the new Student Employment Bureau in the Iowa Union, and on November first he was named manager of the Iowa Memorial Union Dining Services. Rehder lived in the Quadrangle Residence Hall during his junior year in 1929 and was named in The Quadrangler as one of three outstanding men for serving as president of Student Council and president on the YMCA advisory board, as well as proctor of Phi Gamma Delta fraternity and as officer of the Union Board. His position as Union Board advisor continued for a number of years. In July 1933, in addition to managing the IMU Dining Services, he was named assistant director of the Iowa Memorial Union. During 1935, Rehder was advisor of the Homecoming Party, advisor to the Union Board, president of YMCA, president of Student Council, served on the Quadrangle Party Committee and council, and was a member of Chi Phi Pi honorary commerce society. Rehder was involved in so many activities and worked so many hours as a student, he was cautioned in 1929 by Robert E. Rienow, dean of men, to reduce his work and activities in favor of maintaining his grades. Rehder received a B.S. degree in Commerce, with major in business administration, in 1935.

In November 1936, an alcohol-free nightclub, the Silver Shadow, was established in the cafeteria in the lower level of the IMU, at the suggestion of Jess Gorkin, staff of the Daily Iowan student newspaper. On Friday and Saturday nights, entertainment by students in the form of bands, vocalists, dancers, and plays was arranged by Ted Rehder for wholesome student entertainment, while generating a profit of $3,000 per year from one dozen events. Rehder also operated a profitable catering service through Dining Services.

During World War II, Rehder was additionally responsible for feeding 2,300 cadets and officers in the U. S. Navy Pre-flight Training School. The IMU hosted dances as entertainment for the cadets. Rehder was named the first director of Dormitories and Dining Services on July 1, 1946.

During the Vietnam War, Rehder issued a statement urging dormitory residents not to join the student protests at the dormitories on May 12, 1971.

Among his public speaking engagements, Rehder presented at the Food Service Institute, held in Chicago in 1956. He published articles in school and cafeteria magazines, as well as the Journal of American Dietetics and in College and University Business; he served on the editorial board of the latter. He was active in the Association of Big Ten Dormitory and Dining Services Directors, and the National Restaurant Association of Colleges and Universities. Rehder organized the first committee for the National College and University Housing Association. The Iowa City Rotary Club named him a Paul Harris Fellow in June 1986 in appreciation of his support. He served as president of that organization from 1945 to 1946. Rehder was also a member of the Masonic Order. His hobbies relating to his position included collecting cook books and restaurant menus. Mr. and Mrs. Rehder enjoyed holding dinner parties for guests in their home at 1181 Hotz Avenue, as well as their membership in Bridge Club.

Rehder retired in 1976, after serving 47 years with the IMU Dining Services, under five University presidents. In recognition of his service, the students of the Associated Residence Halls dedicated the Theodore M. Rehder Lounge in Quadrangle Residence Hall on October 24, 1981.

Rehder married Alyce Marguerite ("Marge") McConkie, of Nevada, Iowa, on August 16, 1930. Marge's mother was Alyce J. (Haley) Rehder of Dunlap, Iowa. Marge's father, Ernest Lyndon McConkie, was a 1903 graduate of Cornell College in Mount Vernon, Iowa. He sold insurance and real estate, as well as made loans to farmers. In later years, Alyce and Ernest operated the McConkie variety store in Cedar Rapids, Iowa. Ted and Marge had two sons, Robert McConkie, or middle name "Martens," as appeared on his birth certificate, (1935-2009) and Richard Stuart (1939-2005). Robert and Richard attended University High School on the SUI campus. Marguerite Rehder resided in Currier Hall while she attended classes, and she graduated with distinction in June 1929 with a B. A. degree in Education. She also completed one academic year in the Graduate College during 1930 to 1931. She was president of Gamma Phi Beta Sorority and served on the Gamma Phi Beta board during the 1930s. Marge was known as "Conkie" to her sorority sisters. She also served on the committee for the Junior Prom, Hesperia Literary Society, PEO, Apprentice Players, Debate Squad, and YMCA cabinet. In 1928 she was elected to serve on Mortar Board, as well as being named a student Representative of Men and Women of Iowa based on her demonstration of leadership. During 1960 to 1961, she served as president on the board of the Iowa City Public Library. Marge was born in May 1907 and died in November 1974. Theodore M. Rehder died February 24, 1991. Mr. and Mrs. Rehder were members of the First Presbyterian Church in Iowa City, Iowa.