Elwood Olsen Stadium, located at 1401 S. Paxton, is home to the Mustangs’ football, men’s and women’s soccer, and track & field teams. It also plays host to Morningside's commencement ceremony each spring.

The stadium, built in 1940 as a Public Works Administration project, is the largest in the GPAC, boasting a seating capacity of 10,000, and sports a FieldTurf multi-sport playing surface and Daktronics video board and public address.  It also is the site of the Irving F. and Carolyn B. Jensen Press Box, renovated and dedicated in 2019.

The summer of 2025 saw a significant upgrade to the competition surfaces of Olsen Stadium, as the turf and a new track, along with several supporting amenities, were replaced. The turf was previously replaced in 2015.

Morningside University entered into an agreement with the Sioux City School District in 2004, as part of a 99-year lease of then Roberts Stadium, the longtime home of Morningside athletics. That partnership opened the door for a $2.5 million renovation project, including installation of the stadium's first FieldTurf playing surface, a new track, new lighting, and a new parking lot. 

Elwood Olsen, donor and namesake of the stadium, was a long-time resident of Sioux City and a 1938 Morningside graduate. Olsen served his alma mater for 30 years, first as business manager and then as vice president of business until his retirement in 1978. The stadium was dedicated and renamed in Olsen’s honor on August 16, 2005.

As Public School Stadium, the $100,000 initial investment included concrete stands with seating for 10,500, shower and locker rooms, restrooms, consession stands, a public adress system, electric scoreboard, press and radio broadcasting booths, and field lighting of 80 1500-watt lamps. The stadium hosted the three public high schools and Morningside, as it does today, in addition to Trinity Colleges. Construction was completed in 1942 and the facility was dedicated on Sept. 15, 1942.

Olsen Stadium is also home to the Sioux City Community School Distict's football and track & field teams as well as the Sioux City Relays and Sioux City North's Starfest.