Carter Henry Harrison IV ("Harrison"), like his father, Carter Henry Harrison III, was a five term Democratic mayor of Chicago. Harrison served his first four terms around the turn of the twentieth century (1897-1905), with his final term running from 1911 until 1915. Harrison was also Collector of Internal Revenue for the Chicago area during the 1930s and early 1940s.

Harrison's father moved to Chicago in 1855 from Kentucky, shortly after his graduation from Transylvania University (now the University of Kentucky) Law School, and marriage to Sophonisba Preston, Harrison's mother. Upon his arrival in Chicago, Harrison's father invested his money in real estate, and then hung out his shingle as a lawyer and real estate agent. Harrison was born a few years later, on April 23, 1860. In 1873, Harrison's mother was advised to travel to Europe for her health, and Harrison and the rest of the family accompanied her and traveled throughout Germany, Austria, and Switzerland that spring and summer. Harrison's father then returned to Chicago in the fall to tend to his real estate business, but Harrison remained in Germany with his mother and attended school at the Altenberg Gymnasium.

In 1874, Harrison's father was elected to the U.S. House of Representatives, and despite spending much of 1875 in Europe with his family, he was re-elected to Congress in 1876. During this time, Harrison continued his studies at Altenberg, but after his mother died in the fall of 1876 he returned to Chicago.

Upon his return to Chicago, Harrison entered St. Ignatius College (now Loyola University), which was then located near the family's home on Ashland Avenue between Jackson and Van Buren Streets. Harrison graduated from St. Ignatius in 1881, second in a class of two, and then attended Yale University Law School, from which he received a Bachelor of Laws degree in 1883. After law school, Harrison came back to Chicago and practiced law until 1891 when he and his brother, William Preston Harrison, took over the operation of the Chicago Times, which their father had recently purchased.

After completing his second term in Congress, Harrison's father was elected mayor of Chicago and served four consecutive two-year terms, from April 1879 to April 1887. He then took a break from politics, including an eighteen month trip around the world, before being once again elected mayor in 1893. Six months after taking office, however, on the final day of the World Columbian Exposition, Harrison's father was assassinated in his home by Patrick Prendergast on October 28, 1893.

In 1894, Harrison's family sold the Chicago Times, and Harrison focused his energies on his real estate investments until he followed in his father's footsteps and successfully ran for mayor in 1897. Harrison served as mayor from 1897 until 1905, and again from 1911 to 1915. During his first term as mayor Harrison was best known for his bitter, but ultimately victorious, fight against Charles T. Yerkes, the traction railroad baron, who sought a fifty year streetcar concession from the city that Harrison felt was unfair. The traction interests had significant aldermanic support, allegedly obtained through bribery and improper means, and were prepared for Harrison's veto of the proposed ordinance, which they expected to be able to overcome. Harrison, however, went further and took the fight directly to the people, urging them to challenge their aldermen on the issue. Although this move angered some in the Chicago Democratic Party who felt that Harrison had overstepped his bounds, it made Harrison popular with the people, who re-elected him to a second two-year term in 1899.

The Yerkes battle cemented Harrison's reputation as a man of integrity and one who was not afraid to ruffle a few feathers in order to do what he thought was right. Harrison was re-elected again in 1901 and 1903, but declined to run in 1905, when he was succeeded as mayor by Edward F. Dunne, another Democrat. In 1907, the mayoral term was extended from two years to four and Dunne lost his re-election bid to Republican F. A. Busse. Harrison then re-entered the political scene for the 1911 election, in which he defeated Dunne in the Democratic primary, and Republican Charles E. Merriam, a professor at the University of Chicago, in the general election. During what would prove to be his final term as mayor, Harrison was persuaded that the best way to handle prostitution and gambling was to try to eliminate these practices altogether, instead of treating them as necessary evils and attempting to segregate such vices to particular sections of the city where they could be contained and informally regulated by the police, as Chicago had done for many years. This change in tactics led Harrison to a direct confrontation with long-time allies John J. ("Bathhouse John") Coughlin and Michael ("Hinky-Dink") Kenna, the aldermen of Chicago's notorious First Ward, which served as the city's main red-light district. Harrison eventually succeeded in shutting down most of Chicago's houses of prostitution and gambling dens, including the infamous Everleigh Club, but these achievements came at a cost. Without Coughlin and Kenna's political support (which, ironically, had been critical years earlier when he stood up against Charles Yerkes), Harrison lost the Democratic nomination to Robert M. Sweitzer in 1915 and moved to the sidelines of Chicago politics, although he remained active in the Democratic Party at the national level throughout the remainder of his life.

When America entered World War I, Harrison desperately wanted to participate, but was too old to serve in the military. He lobbied heavily for an appointment to a meaningful position that would allow him to, if not see action, at least be able to "hear the big guns." Eventually, Harrison was made a Captain in the American Red Cross and stationed in Toul, France, a few miles behind the front lines, where he worked to help make life more comfortable for the American troops stationed and recovering at the several field hospitals located there.

Following the war, Harrison spent most of the 1920s traveling. He took multiple trips around the world, along with shorter excursions to Europe and Africa. By the early 1930s, however, reversals in the stock market had diminished his personal fortune and Harrison decided to return to work, even though he was now over seventy years old. Relying on his political connections, Harrison was appointed Collector of Internal Revenue for the Northern District of Illinois by President Franklin D. Roosevelt in 1933. It was thought that this would be a relatively short-term position, but Harrison ended up holding the post until the end of 1944, when he finally retired from public service for good at the age of 84.

Harrison was a both an outdoorsman and a scholarly patron of the arts. He loved hunting and fishing, and throughout his life went on numerous expeditions into the wilderness in search of big game or the perfect trout stream, including hunting and fishing trips to the Sierra Nevada Mountains, India, Indochina, and Africa. In 1940, when he was eighty years old, Harrison and his long-time friend Oscar Mayer (the Chicago meat-packer), each bagged a 150 pound buck on their annual hunting trip to northern Michigan. Harrison also had somewhat of a reputation as a trencherman, and favored a "Kentucky Nightcap" of bourbon before retiring for the day. At the same time, however, Harrison was an avid art collector and regular at the Chicago symphony and opera. Before his death, he donated his substantial art collection to the Art Institute of Chicago, including works by Paul Gauguin, Childe Hassam, Mary Cassatt, Claude Monet, and Toulouse-Lautrec. In recognition of his support, the Art Institute ultimately named Harrison a Benefactor and Governing Life-Member of the museum. According to his daughter, Harrison's "light-reading" usually consisted of poetry or the ancient Greek classics, and he read a chapter of the Bible each night throughout his life in fulfillment of a boyhood promise to his mother.

Harrison died on Christmas Day, 1953, at the age of ninety-three. On New Year's Eve of that same year, the Chicago City Council passed a resolution recognizing his accomplishments as mayor, Collector of Internal Revenue, world traveller, and patron of the arts. The resolution stated, in part, that "from such men as Carter H. Harrison, men of integrity, vision, high civic ideals and unswerving zeal, we shall take example." Harrison led a life full of accomplishments and achievements, and appeared to have no regrets. The only disappointment that seemed to stick with him was the failure of his son, Carter H. Harrison V, to have a son that could carry on the family name. Much to Harrison's chagrin, it was his daughter, Edith Harrison Manierre, who bore him two grandsons, while his son gave him four granddaughters.