Maucker Union has served as the University of Northern Iowa's (UNI) campus union since its opening on April 7, 1969. Efforts to better conceptualize a student union took place in the 1950s, when a campus survey sought to identify what services and facilities were most wanted in a union by the campus community. Prior to Maucker Union, the Commons building housed the school's union. In 1959, a union consultant was hired to make recommendations about remodeling the existing Commons building in order for it to serve as the union. Once the project was underway, it became apparent that redoing the Commons in this way was not feasible.

UNI president J.W. Maucker made the decision in 1964 to split the Commons construction project into two distinct parts. The first focused just on remodeling the Commons as a dining center, while the second focused on building an entirely new union buildng based on the union consultant's recommendations. Groundbreaking for the union, later named in Maucker's honor, took place in March 1967.

In creating Maucker Union, the goal was to assist in the development of various programs and opportunities on campus, including social, recreational, cultural, and informational. This was to be accomplished through the use of the Union's facilities, services, and resources in order to best serve the campus community's interests.

Early on in the Union's history a Union Policy Board, reporting to the university's president, was established to recommend policies for the Union's operations, facilities use, and programming. It also reviewed recommendations regarding the Union and fiscal matters.

Various updates have been made in the Union since its initial construction, including a new roof, additional stores, renovations to make spaces accessible, computer labs, and a food court.