Brent worked as a law clerk for Mattoon attorney Harlan Heller during law school and was hired as an associate upon passing the bar. Harlan Heller was considered by his peers as one of the most outstanding trial attorneys of his era. Brent credits his success as a trial lawyer to the invaluable experience he obtained from Harlan and second-chairing many jury trials with Harlan as the lead attorney. 

Brent is an experienced and successful trial attorney. He has obtained substantial jury verdicts for his clients in both state and federal court. They include a $1,269,815 verdict in Coles County and the largest wrongful death verdict in the history of Effingham  County, being more than $3 million. In October 2023, he obtained a wrongful death verdict in Piatt County for $1 million. 

He has appeared in circuit court in 42 counties throughout Illinois. He also has tried cases to verdict in the U.S. District Courts for the Central and Southern Districts of Illinois. He also has prosecuted appeals to the Illinois Appellate Court, the Illinois Supreme Court, and the U.S. Court of Appeals for the Seventh Circuit in Chicago. 

Brent is a member of the Illinois State Bar Association and is a past president and current member of the Coles-Cumberland Bar Association. Putting his journalism background to good use, Brent was on the Illinois Bar Journal Editorial Board from 1994 to 2006 and served as editor-in-chief from 2004 to 2006. 

He was appointed by the Illinois Supreme Court in 2008 to serve on the IPI Civil Committee on Jury Instructions. This committee prepares model jury instructions that are used by judges and lawyers in civil jury trials throughout Illinois' 102 counties. Brent  Holmes served for 9 years, including being named vice chair in 2016. 

Brent has accepted pro bono cases from the Land of Lincoln Legal Assistance Foundation through the Coles-Cumberland Bar Association Pro Bono Project. For this work, he was honored as the 2011 recipient of the Joseph R. Bartylak Award, recognizing outstanding volunteer service in representing persons who cannot afford to pay for legal representation. 

In 2022, he was recognized by Legal Services Corporation, a national not-for-profit legal services agency, in Chicago, the first time in 13 years that the award had been bestowed upon an Illinois attorney. 

Brent is active in the community and serves on the Immaculate Conception Church Finance Council. He also serves on the board and is past president of The Haven board of directors. The Haven operates a homeless shelter and soup kitchen and has programming to help its guests obtain housing, employment, and to become self-

sufficient. He formerly served on the board of education of St. Mary School and Mattoon Golf and Country Club.

Brent and his wife Kathy have two daughters and four grandchildren. Brent is also an instrument-rated pilot and has flown his plane around the United States and Canada.