Open wheel racing at the track dates back to 1937. AAA sanctioned races in 1937–1939, 1941, and 1946–1955. The track was paved in 1954.
USAC sanctioned Championship car races from 1956–1979. In 1980, the race switched to a CART/Champ Car race, and continued through 2006. IndyCar started holding races at the track in 2004, and thus for a brief time from 2004-2006, the track hosted both a Champ Car race (June) and an IndyCar race (August).
Starting in 2007, IndyCar became the lone event. The race was put on hiatus for 2010, stemming from management difficulties regarding payment of sanctioning fees. In 2011, the race returned and continues to be held.
For most years starting in 1949, Milwaukee traditionally hosted the first race following the Indianapolis 500. From 1947 to 1982, Milwaukee generally hosted two races, the first race right after Indy in June, and the second in August or September. The latter sometimes in the days surrounding the Wisconsin State Fair.
After 1982, the second race was dropped. With only one race annually going forward, the track decided to keep the traditional June "right after Indy" date.
In 1986, the race was scheduled for Sunday June 1. However, due to rain on May 25–26, the Indianapolis 500 was postponed to Saturday May 31. After discussions with track, television, and series leaders, the Milwaukee race was pushed back one week to make the accommodation.
From 2004-2006, when both Champ Car and IndyCar were holding races at the track, Champ Car still utilized the June date, while IndyCar chose to hold their race in late July. In 2007, when IndyCar became the lone open wheel race at the track, there was a renewed interest in placing the event on its traditional June date immediately after Indy. This arrangement lasted only three years (2007-2009), as the race was put on hiatus for 2010.
When the race revived for 2011-2013, for a variety of reasons, race organizers decided to move the race to the Saturday of Father's Day weekend. Detroit took the weekend immediately after Indy, and Texas maintained its position on the second weekend of June. Starting in 2014, the race moved permanently to August, reviving the old state fair date.
From 1950 to 1987, the June race was called the Rex Mays Classic, in honor of Rex Mays, a two-time AAA national champion killed in a race in 1949. Meanwhile, the August race was named the Tony Bettenhausen 200 from 1961 to 1982 in reference of Tony Bettenhausen, who died after a crash in 1961.
In the 1963 Tony Bettenhausen 200, Jim Clark and Team Lotus became the first to win an American Championship race with a rear-engined, monocoque car. After finishing second in that year's Indianapolis 500, Lotus decided to run the car again at Milwaukee and Trenton. Clark and teammate Dan Gurney broke the track record by over a second in qualifying, and Clark led all 200 laps to win, lapping the entire field except for second place A. J. Foyt.
For most years from 1949–2009, Milwaukee traditionally hosted a Championship/Indy car race the weekend immediately following the Indianapolis 500. Numerous drivers managed to win both races in the same year in back-to-back weeks.1947: Bill Holland
1956: Pat Flaherty
1964: A. J. Foyt
1971: Al Unser, Sr.
1974: Johnny Rutherford
1982: Gordon Johncock
1983: Tom Sneva
1988: Rick Mears
1994: Al Unser, Jr.
2000: Juan Pablo Montoya (Indianapolis was an IRL race, Milwaukee was a CART series race)
1937: Race shortened due to scoring error.
1994: Race shortened due to rain.
2005-06: CCWS races used a time limit (1:45), standard for all CCWS races.