Mark Steven Kirk (born September 15, 1959) is an American retired politician and attorney who served as a United States senator from Illinois from 2010 to 2017, and as the United States representative for Illinois's 10th congressional district from 2001 to 2010. A member of the Republican Party, Kirk describes himself as socially liberal and fiscally conservative. As of 2026, he is the last Republican to represent Illinois in the U.S. Senate.
Born in Champaign, Illinois, Kirk graduated from Cornell University, the London School of Economics, and Georgetown University Law Center. He practiced law throughout the 1980s and 1990s. He joined the United States Navy Reserve as a direct commission officer in the intelligence career field in 1989 and was recalled to active duty for the 1999 NATO bombing of Yugoslavia. He participated in Operation Northern Watch in Iraq the following year. He attained the rank of Commander and retired from the Navy Reserve in 2013.
Kirk was elected to the House in 2000. During his fifth term in November 2010, he won two concurrent elections: to finish the final months of former senator Barack Obama's term and to serve the next six-year term. He was sworn in on November 29, 2010, and began a six-year Senate term on January 3, 2011. In January 2012, Kirk suffered a stroke; almost a full year passed before he returned to his senatorial duties. In 2016, Kirk ran for re-election to a second full term, but was defeated by Democrat Tammy Duckworth.
Kirk was born in Champaign, Illinois, the son of Judith Ann (Brady) and Francis Gabriel "Frank" Kirk. After graduating from New Trier East High School in 1977 he attended Blackburn College in Carlinville, Illinois, for two years, before briefly attending the Autonomous University of Mexico and subsequently transferring to Cornell University, where he graduated cum laude with a bachelor's degree in History. While at Cornell University, Kirk served as the president of The Seal and Serpent Society. Kirk later obtained a master's degree from the London School of Economics and a Juris Doctor (JD) from Georgetown University Law Center.
While Kirk was an undergraduate student at Cornell University he held a work–study job supervising a play group at the Forest Home Chapel nursery school. After getting his master's degree, Kirk taught for one year at a private school in London. He later stated in speeches and interviews that he had been a nursery and middle school teacher. A leader at the church which housed the nursery school expressed her belief that Kirk overstated his role there, saying Kirk was "just an additional pair of hands to help a primary teaching person." In discussing problems in the educational system early in his congressional career, Kirk addressed the brevity of his teaching career: "I did leave the teaching profession, but if we had addressed some of the teacher development issues, which I want to raise with you, I might have stayed."
After college, Kirk worked in Congressman John Porter's office, ultimately becoming chief of staff. After leaving Capitol Hill in 1990, he worked at the World Bank and as an aide at the State Department on the Central American peace process. Kirk spent two years practicing international law and four years as counsel to the House International Relations Committee.
Kirk was commissioned as an intelligence officer in the United States Navy Reserve in 1989.
In 1999, Kirk was recalled to active duty in Operation Allied Force for the bombing of Yugoslavia. He served from April 10 to June 6, 1999, as the intelligence officer of VAQ-209. VAQ-209 was combined with three other EA-6B squadrons to form an ad hoc unit called Electronic Attack Wing Aviano, Italy. VAQ-140 had tactical command of the combined unit. In May 2000, the National Military Intelligence Association bestowed the organization's Vice Admiral Rufus L. Taylor Award to Intelligence Division Electronic Attack Wing Aviano, Italy.
In March and April 2000, Kirk trained with an EC-130 squadron based in Turkey. Kirk took a flight over Iraq as part of Operation Northern Watch, which enforced a no-fly zone over the northern section of Iraq. In a speech on the floor of the House in 2003, Kirk stated: "The last time I was in Iraq I was in uniform, flying at 20,000 feet, and the Iraqi Air Defense network was shooting at us". Kirk later clarified his statement, indicating that there is no record of his aircraft being fired upon and that he had incorrectly recalled the incident.
During his tenure in the military, Kirk was twice counseled by the Pentagon, after incidents in which he was accused of conducting political business while on duty. On one occasion Kirk commented on Rod Blagojevich's arrest and posted a tweet while on duty with the Navy in Afghanistan. According to the Pentagon, Kirk was required to sign a statement acknowledging he knew the rules before returning to active duty. Kirk denied that he had ever improperly mixed politics with his military service.
Kirk served three individual two-week reserve deployments in Afghanistan, with the latest concluding in September 2011.
Kirk retired from the Navy Reserve in May 2013, after 23 years of service. A formal military retirement ceremony was held for Kirk on December 16, 2014.
In the official photograph of his retirement ceremony, Kirk's awards include:
Defense Meritorious Service Medal
Joint Services Commendation Medal
Navy and Marine Corps Commendation Medal
Joint Service Achievement Medal
Navy and Marine Corps Achievement Medal