Charles Nelson Reilly was born to Charles Joseph Reilly, an Irish-American and Catholic, and Signe Elvera Nelson, a Swedish-American and Lutheran. As a child, he entertained himself with improvised puppet theater performances, showcasing his creative talents at a young age.
However, Reilly's life took a dramatic turn in 1944 when he witnessed the devastating Hartford circus fire in Connecticut. The tragedy, which killed 167 people and injured 700, left a lasting impact on Reilly, instilling in him a lifelong fear of fires. As a result, he never attended public performances of theater and circus again, fearing another catastrophic event.
Despite this traumatic experience, Reilly's passion for show business remained strong. He initially aspired to become an opera singer and took lessons at the University of Hartford Hartt School. Although he eventually realized his voice skills were inadequate, he turned to theater and made his film debut with a minor role in "A Face in the Crowd" (1957).
During the late 1950s, Reilly appeared regularly in comic roles in off-Broadway theatrical performances. In 1960, he gained critical attention for his small but notable part in the Broadway musical "Bye Bye Birdie". The following year, he joined the cast of the musical "How to Succeed in Business Without Really Trying", winning his first Tony Award in 1962 for his performance.
Reilly continued to appear in Broadway shows throughout the decade, solidifying his reputation as a talented actor. In the 1960s, he began making television appearances, starting with guest roles in panel shows and television advertisements. He eventually landed a key role in the television series "The Ghost & Mrs. Muir" from 1968 to 1970.
In the 1970s, Reilly became a regular on game shows and children's series, such as "Match Game" and "Uncle Croc's Block". He also started teaching acting to others while shifting his career from acting to directing. Reilly directed numerous Broadway shows and was nominated for a Tony Award for directing in 1997. He also directed several television episodes.
In the 1990s, Reilly had guest roles in television series such as "X-Files" and "Millennium". He continued to work in television and theater until the 2000s, when he primarily focused on his autobiographical play "Save It for the Stage: The Life of Reilly" and its film adaptation.
Throughout his career, Reilly was known for his versatility, talent, and dedication to his craft. Unfortunately, his life was cut short due to respiratory problems, which led to his retirement and eventual death from pneumonia in 2007.