The Centennial Union building project began on May 17, 1960 with a groundbreaking ceremony. The Main building had functioned as the Luther College center prior to the construction of the Centennial Union, but the college required a larger building to house the various offices, food facilities, and student lounge areas. Since Luther College had seen virtually no new buildings during the previous years of depression and war, President Ylvisaker knew that it was essential to expand. After much planning by students and faculty the Centennial Union became the sixth major building of the Ylvisaker administration. Situated just north of Main and south of the Center for Faith and Life, the Centennial Union lies at the top of a bluff on the west side of campus.
Luther College hired Porter Butts, of the University of Wisconsin, as the primary consultant in 1958. At the beginning of the school year in 1959, a new charge appeared in the student tuition to raise money for the construction. Each student was to pay $12.50 per semester for the use of the Union. In addition, the college was given a federal loan of $750,000. The original parts of the Union, which excepted a section of the north end first floor and the entire north wing on the top floor, cost $1,312,519. To finish the Centennial Union, a second loan was needed of $996,000 from the Department of Housing and Urban Development. These north wing sections were not completed until 1973 at a cost of $958,000.
The Centennial Union was built for several purposes, so it required a number of interesting additions. The Union needed to house the bookshop, College Chips, Pioneer yearbook, the student post office, and the Admissions offices. The building was also designed to have wide open spaces acting as lounges for the students. For recreational purposes a bowling alley was added as well as places to shoot pool. A dim lit cafe, called Dante's, was placed on the lower floor as a place to offer live entertainment. On the first and second floors of the north wing, two dining rooms were placed, as well as multiple smaller conference rooms for special occasions. It was suggested by Warren Berg that these rooms be named after winners of the Nobel Prize for Peace: Hammarskjold, Nansen, Soderblom, Schweitzer, Mott, Borlaug, King, Addams, Marshall, and Williams. The largest area of the Centennial Union was given to the new dining facility where every student on campus could eat at the same time, something that had not been accomplished since World War II. The Union also has the distinction of being the first building on the Luther College campus to be air-conditioned.
The Centennial Union was named for the Luther College 100th Anniversary, which was being observed in the 1960-61 school year. On May 5, 1961 the cornerstone was laid by A. Alvon Nelson (class of 1929) who read Joshua 24:27 to commemorate the event. The entire building was not fully completed until 1973.
In 2006 Luther College began a $2.6 million renovation and addition to the Centennial Union. When it was finished in 2007 the Union now contained the major dining halls; Marty's (formerly Dante's, now a cyber-cafe); Oneota Market (a food pavilion connected to a student lounge with open seating, a fireplace, a solarium overlooking the Oneota Valley, and computer workstations); a centralized mail center; a new, large book shop; the diversity center; the student-run radio station (KWLC); lounges; conference rooms; the college president's and vice-presidents' offices; offices for student services, student government, student organizations, and student publications; career development offices; public information offices; student life and admissions offices; an art gallery; and banquet and community dining facilities. With all of these additions, there was still room to place an entryway with a 30-foot-tall glass-enclosed atrium.
In October of 2006 the Union was rededicated as the Bert M. and Mildred O. Dahl Centennial Union. The Dahl family contributed the funding which made the renovation possible. Orville Dahl also aided in drawing up the campus plans in 1957 which included the first Union to be built.