Third Unitarian Church of Chicago was founded in November 1868. The original members had gathered based on a newspaper ad announcing a meeting to start a Unitarian church on Chicago’s Near West Side where its first building was located. After losing its first building at Monroe and Laflin streets to the Chicago fire, the church moved several times before coming in 1936 to its current location at Mayfield and Fulton streets, near the city’s western boundary of Austin Boulevard.

The architecture of the new building was unorthodox and pioneering for its day, symbolizing the philosophy and spirit of the church. When the church was enlarged in 1956, 19 ceramic tile portrait murals of Unitarian "Saints" (wise people that we admire) were created to add to the uniqueness of the sanctuary. The church was declared a landmark by the Chicago City Council in 1960. The "Saints" include Buddha, Socrates, Jesus, Confucius, Thomas Jefferson, Woodrow Wilson, Harriet Tubman, Jane Addams, and others.

Nineteen ministers have served Third Church since its founding. Dr. Rowena Morse, minister 1911-1919, was the first woman to receive a Ph.D. from a European university. She had been refused admittance to Harvard Divinity School because of her sex, but became the first women to speak in the chapel there in 1921 (the second was in 1972).

Dr. Walton E. Cole, minister 1928-32, gained national prominence by opposing ultraconservative Father Charles Coughlin over the radio. He was followed by Dr. Edwin H. Wilson who signed the original Humanist Manifesto in 1933. Dr. Edwin T. Bueher served the longest of any minister at Third Unitarian, 1941-69. During his ministry, membership was close to 250 and the Sunday School had more than 100 children.

Rev. Donald H. Wheat served as minister in 1969-96 during a period of change. The congregation became very active in the Civil Rights and antiwar movements. In 1978 as the Austin community changed from predominantly European American to African American, a slim majority of members voted to move the church, but more than 100 members decided to remain in the current location. The congregation grew again and has maintained a cordial and welcoming relationship with its neighbors and has worked for community improvement.

Rev. Dr. Michelle Bentley, the first African American female settled senior minister in the Unitarian Universalist denomination, served four years, 1998-2002. Her ministry was characterized by community outreach and attracting new members, especially young people and African-Americans.

The current minister, Rev. Brian Covell, was called to be minister in 2003 and was officially installed in 2004.