James D. Oberweis (born June 10, 1946) is an American businessman, investment manager, and politician from the state of Illinois. The former owner of Oberweis Dairy in North Aurora near Chicago, he served as a member of the Illinois Senate, representing the 25th district from 2013 to 2021.
Oberweis has been active in Republican politics for more than two decades and has sought several statewide and federal offices. He was a candidate for the Republican nomination for the United States Senate in 2002 and 2004, and for Governor of Illinois in 2006. He was the Republican nominee for Illinois's 14th congressional district in both a March 2008 special election and the November 2008 general election. In 2012, Oberweis was elected to the Illinois Senate, representing the 25th district. He later became the Republican nominee for the U.S. Senate in 2014, challenging incumbent Senator Dick Durbin. In 2020, he was the Republican nominee for Illinois's 14th congressional district. Following his move to Florida, Oberweis entered the race for the U.S. House seat being vacated by Byron Donalds in the 2026 election in Florida's 19th congressional district.
Education
After graduating from Marmion Academy in Aurora, Illinois, he attended the University of Illinois at Urbana–Champaign, where he joined Phi Kappa Tau fraternity. He spent a year abroad, studying at Technische Hochschule Darmstadt. He received a Bachelor of Arts from Illinois, and then a Master of Business Administration from the University of Chicago.
Career
In 1968, Oberweis became a junior high school teacher at Waldo Junior High in Aurora, teaching math and science. His father, Joe, had died in 1984, and Joe's successor (and Jim's older brother) John suffered an incapacitating stroke in 1986; after Jim's purchase he turned day-to-day operations over to outside presidents who embarked on acquisition programs highly leveraged with debt. Elaine Oberweis (University of Chicago MBA '89)
He remained active in the investment field. In 1987, he founded Oberweis Emerging Growth Fund. In 1989, he established Oberweis Asset Management (OAM). OAM specializes in "small-cap growth equities investing", and has individual accounts for institutional investors and a family of mutual funds for individual investors. As of 2015, OAM had about $2 billion under management.
Oberweis moved the Oberweis Dairy from Aurora to its present location in North Aurora. He also began a chain of company-owned dairy stores, and has maintained a dairy delivery business to homes in the Chicago area. A franchise program began in 2004, to expand the dairy business outside of northeast Illinois.
Television
Oberweis became a financial news anchor and host of the show Catching Winners Early on the Financial News Network. In Chicago, Oberweis became a regular guest on the Ask an Expert show. Oberweis was also a popular guest on CNBC, CNN, and Bloomberg TV.
2002 U.S. Senate election
In 2002, Oberweis sought the Republican nomination for U.S. Senator, but lost in the primary, finishing second of three with 31%.
2004 U.S. Senate election
Oberweis ran for Senator again in 2004, but again lost in the primary, finishing second of seven with 24%.
Oberweis's 2004 campaign was notable for a television commercial in which he flew in a helicopter over Chicago's Soldier Field and claimed enough illegal immigrants came into America in a week (10,000 a day) to fill the stadium's 61,500 seats.
During his 2004 Senate campaign, Oberweis appeared in television commercials for Oberweis Dairies. The Federal Election Commission ruled that this was an improper corporate contribution to the campaign, and fined Oberweis $21,000 for violation of campaign finance law.
2006 gubernatorial election
In 2006, Oberweis sought the Republican nomination for Governor of Illinois. He started his campaign in April 2005. He lost in the primary, finishing second of five with 32%. The winner of the primary was Judy Baar Topinka, who was defeated by Democrat Rod Blagojevich in the general election 49.8%–39.3%, with Rich Whitney, the Green Party candidate, receiving a little over 10.3%. He won the primary for the special election for the remainder of Hastert's unfinished term with 56%. He also won the primary for the general election for the next term, with 58%. In 2013, as State Central Committeeman, Oberweis led the effort to oust former Illinois Republican Party Chairman Pat Brady after his controversial public support of same-sex marriage. While Oberweis's efforts were unsuccessful, Brady eventually resigned because of the controversy.
Oberweis did not run again for the State Central Committee for the election in April 2014.
State senate
In the 2012 general election, Oberweis won the 25th State Senate seat previously held by Chris Lauzen, his former GOP primary rival in the 2008 congressional race. He had announced his bid in September 2011. He defeated his Democratic opponent, Corinne Pierog, 57.5%–42.5%. In the 2016 general election, Oberweis again defeated Pierog, this time 54.7%–45.3%.
In October 2018, Oberweis was appointed as the Senate Republican Whip. He did not run for re-election in 2020.
Committee assignments
- Commerce and Economic Development
- Environment and Conservation (Minority Spokesperson)
- Executive
- Subcommittee on Election Law
- Labor (Minority Spokesperson)
- Revenue
- Transportation; Subcommittee on Election Law
- Subcommittee on Capital
2014 U.S. Senate election
Oberweis was the Republican nominee for the 2014 Senate election, for the seat held by Democrat Dick Durbin. He defeated Doug Truax in the Republican primary with 56% of the vote. He was defeated by Durbin in the November election.
2020 congressional elections
Oberweis announced he would run again for Illinois's 14th congressional district, challenging Democratic incumbent Lauren Underwood. On March 17, 2020, he won the Republican nomination, narrowly defeating six other candidates including fellow state Senator Sue Rezin, and businesswoman Catalina Lauf.
On November 4, Oberweis, leading by less than 900 votes in the incomplete vote count, declared himself the victor. This came despite the fact that the race had not been called by media outlets and there were still thousands of uncounted mail-in ballots. That same day, Oberweis began sending out fundraising appeals to fund fees associated with a potential recount. Oberweis did not concede, and stated that he was considering all legal options, including a possible recount.
Jim Oberweis attended the congressional new member orientation on November 13. He began calling for a "discovery recount" on November 18.
According to the official canvass by the Illinois State Board of Elections, Lauren Underwood received 203,209 votes (50.67 percent) and Jim Oberweis received 197,835 votes (49.33 percent).
In January 2021, Oberweis filed a notice of contest with the U.S. House of Representatives, alleging that irregularities in the vote recount would make him the winner of the election. On May 12, 2021, the House rejected Oberweis's challenge.
2026 congressional election
In March 2025, Oberweis became the first Republican to announce their congressional campaign to replace Byron Donalds in the 2026 election in Florida's 19th congressional district.
Electoral history
{| class="wikitable"
|+ Electoral History – Summary
|-
! Year !! Office !! Election type !! Result
|-
| 2002 || U.S. Senate || Primary || style="background-color: lightpink;"|Lost
|-
| 2004 || U.S. Senate || Primary || style="background-color: lightpink;"|Lost
|-
| 2006 || Illinois Governor || Primary || style="background-color: lightpink;"|Lost
|-
| 2008 * || U.S. House of Representatives || General || style="background-color: lightpink;"|Lost
|-
| 2008 || U.S. House of Representatives || General || style="background-color: lightpink;"|Lost
|-
| 2012 || Illinois Senate || General || style="background-color: lightgreen;"|Won
|-
| 2014 || U.S. Senate || General || style="background-color: lightpink;"|Lost
|-
| 2016 || Illinois Senate || General || style="background-color: lightgreen;"|Won
|-
| 2020 || U.S. House of Representatives || General || style="background-color: lightpink;"|Lost
|-
| 2026 || U.S. House of Representatives || Primary || —
|}
<nowiki>*</nowiki> Special election