Marty O’Donnell, the composer behind the iconic “Halo” video game soundtrack and other well-known musical projects, is running against Democratic Rep. Susie Lee for Nevada’s 3rd Congressional District after winning the Republican primary in June. O’Donnell previously ran for the seat in 2024 and finished fourth in that year’s Republican primary.

O’Donnell has contributed millions of dollars of his own money to his campaign and received endorsements from President Donald Trump and Nevada Governor Joe Lombardo. Trump described O’Donnell as a “World-Class Composer and Entrepreneur” while endorsing his campaign and citing issues including tax cuts, energy production, border security, military support and Second Amendment rights.

During his campaign, O’Donnell has highlighted his career in music and entertainment, telling voters, “I wrote Halo. I wrote the jingle for the Flintstones song.”

O’Donnell spoke at the Republican Midterm Convention on Thursday. He said in his remarks that his decision to enter politics was driven by concerns about the future his grandchildren will inherit.

“I am running because of my grandkids,” O’Donnell said. “I think about the country that they are about to grow up in, so I wouldn’t stay on the sidelines.”

He has previously criticized Lee and congressional Democrats over several issues, including military pay, congressional stock trading and federal accountability. He argued that members of Congress should face restrictions on stock trading and has specifically criticized Lee over her stock transactions. In his RNC address, O’Donnell accused Lee of "enriching herself" through stock trading during her political service.

O’Donnell's campaign has also emphasized small businesses, family finances, community safety and reducing government burdens on working households. He has also invoked former National Institutes of Health Director Anthony Fauci in arguments surrounding accountability for government officials, saying, “We don't need to plead the 5th. I am looking at you, Fauci.”

Nevada’s 3rd District covers parts of the Las Vegas area and has been closely contested in recent elections. Lee won reelection in 2022 with 52 percent of the vote and in 2024 with 51.4 percent, while Trump carried the district by less than one percentage point in the 2024 presidential election.

The congressional race is one of the contests being watched closely as both parties compete for control of the House.