[1] The ballfield was regularly used as the central hub of Chehalis sporting activity for decades, including hosting games for several Negro League teams in the 1920s.

[1] After deeding the parcel, originally a business share of the Chehalis Land & Timber Company, Millett bought several surrounding tracts to increase the park's size.

[7][8] Millett Field was used as home turf for the Chehalis Bearcat's football team until 1932, moving to new grounds after flooding issues and the loss of the grandstand prohibited large crowds from attending the games.

[27] The largest recorded crowd at the field during this period was a Chehalis Bearcats football win over Hoquiam in an annual Armistice Day game in 1929.

[33][34] During the late 1920s and into the 1930s, an annual baseball competition was held at Millett Field between the Portland and Seattle teams of the Pacific Telephone & Telegraph Company.

[36][37] Concrete tennis courts were built in the southeast section of the park in 1925 with financing provided by a local Business and Professional Women's Club.

[38] Various non-athletic events, such as military training, national and local celebrations, festivals, carnivals, and early Decoration Day observances were held at Millett Field since its grand opening.

[42] The football field was permanently moved to the south of the grounds away from the baseball diamond in 1925, providing annual savings and maintenance due to the necessary conversions of the two sports.

[50][51] The Chehalis Bearcat high school baseball team played their first night game at the field in May 1954 against crosstown rivals, the Centralia Tigers.

[55] Due to a railroad strike, Millett Field hosted the 1956 Northwest Regional Babe Ruth tournament that was originally planned to be held in Cheyenne, Wyoming.

The stadium was overhauled in two days to provide an electric scoreboard, additional bleachers, and preventative measures against non-paying spectators from viewing the games.

Due to a flood in November 1986, approximately 10,000 gallons of pentachlorophenol, a protentional carcinogenic chemical used in the process of treating lumber, was leaked into the field and nearby neighborhood.

[1] An attempt in 2006 to consider the land surplus for use as a flood mitigation tool did not materialize,[61] however a playground area, built with the cooperation of a local fitness club and the city was unveiled that year.

[1] Millett Field's home plate was positioned in the northern corner of the ballpark, with the Crossarm Mill factory, the downtown core, and Park Hill behind the grandstand.