Mary Cosby

Cosby was announced as a cast member of The Real Housewives of Salt Lake City in September 2020 and appeared as one of the show's original housewives. NBCUniversal executive Noah Samton said the series was conceived after the production team discovered Cosby and then developed a broader cast for a Salt Lake City installment of the franchise.

She appeared during the show's first two seasons but did not attend the second-season reunion and did not return as a full-time cast member for season three. Cosby returned as a friend of the housewives in season four and was promoted back to the main cast for season five. She also appeared in season six, while Bravo's coverage has connected her later storylines with her faith, her family and the death of her son, Robert Cosby Jr.

Cosby's grandmother, Rosemary "Mama" Cosby, founded Faith Temple Pentecostal Church in 1968. After Rosemary's death in January 1997, Cosby became closely associated with the church and later served as its first lady alongside Bishop Robert Cosby Sr. The church became an important part of Cosby's public identity before and during her reality television career.

Faith Temple has faced allegations from former congregants and some of Cosby's RHOSLC castmates that it operated as a cult and engaged in financial misconduct. Cosby has denied the allegations, calling them false and ridiculous. The claims became the subject of the TLC docuseries The Cult of the Real Housewife, which examined the church, Cosby's family history and her marriage to Robert Cosby Sr.

Cosby married Robert Cosby Sr. in Chicago on September 28, 1998, following the death of her grandmother the previous year. Robert had been married to Rosemary Cosby and was therefore Cosby's step-grandfather, although the couple are not biologically related. Cosby has described the marriage as arranged and said that it reflected her grandmother's wishes for her to take over the church and its leadership role.

Through the marriage, Cosby became the first lady of Faith Temple Pentecostal Church. Robert Sr. has appeared at the first-season reunion of The Real Housewives of Salt Lake City, where he praised Cosby as a wife, mother and co-pastor. The couple have one son, Robert Cosby Jr., who died at age 23 on February 23, 2026.

In April 2021, Cosby was charged with unlawfully providing shelter to a runaway and contributing to the delinquency of a minor. She pleaded not guilty in August 2021, and the charges were dropped in September 2022.

In September 2024, Cosby sued two executives of United Security Financial, accusing them of embezzlement in connection with the church's financial operations. The church and Cosby's marriage also became the focus of public scrutiny through The Cult of the Real Housewife. Cosby rejected the documentary's claims and continued to deny allegations concerning Faith Temple.