American Family Field was one of the largest construction projects in Wisconsin history. It was built with US$290 million of public funds from a 0.1% sales tax that began January 1, 1996, and ended on March 31, 2020. The tax was applied on purchases in Milwaukee County and four surrounding counties: Ozaukee, Racine, Washington, and Waukesha. The tax was controversial, in part because of the notion of using public funds for a privately owned sports team. The state senator who cast the deciding vote in the funding bill, George Petak of Racine, lost a recall election based on his vote for the stadium.
On November 9, 1996, groundbreaking took place in a parking lot behind County Stadium. Originally scheduled to open in 2000, American Family Field's construction was delayed after three construction workers were killed in an accident. A Lampson Transi-lift crane 3 (nicknamed "Big Blue"), brought in to build the roof, collapsed while lifting a 450-ton roof section, during windy conditions, on July 14, 1999, killing three workers. A camera crew was filming construction of the stadium on that day and captured the collapse on video as it occurred. Repair work and an investigation forced the Brewers to stay in County Stadium for one more year, until 2001. There was some talk of having the Brewers move to American Family Field in the middle of 2000, but it was determined that too many issues would need to be resolved for it to be a realistic possibility.
The stadium has a retractable roof, built in a unique fan-shaped style, with the roof panels opening and closing simultaneously in a sweeping manner from the first- and third-base sides toward center field. The complex and massive roof was a significant factor in the $392 million cost of the stadium. It allows the seating area to be heated 30 °F (17 °C) warmer than the outside temperature when closed, allowing games to be played in inclement weather and in more comfortable conditions than an open-air stadium. For example, when it is freezing outside, the temperature inside will be 62 °F (17 °C). The idea of the stadium having a retractable roof had been considered right away in the initial design, as to help counter the unpredictable Wisconsin weather in the early spring and late autumn.
The design team was appointed after a design competition in the mid-1990s. The architectural concept for the stadium was developed by the Los Angeles-based sports and entertainment team NBBJ, who worked closely with a Los Angeles-based team of engineers Arup, who were responsible for all stages of the structural and building services engineering design for the stadium, with the exception of the mechanical mechanisms that move the roof structure. The original versions of these mechanisms were designed by Mitsubishi Heavy Industries America as part of a design and build contract, but they have now been replaced by new designs after their failure. The executive architect responsible for the delivery of the final stadium design was a Dallas-based team of HKS, Inc. In addition to these major players there were a significant contributions from local teams including Eppstein Uhen Architects.