Sarah Ophelia Colley was born in Centerville, Tennessee. She graduated from what was then Nashville, Tennessee's most prestigious school for young ladies, Ward-Belmont. Her family, relatively affluent by the standards of the area and the day, was somewhat scandalized by her entry into "show business". At first, her involvement was more as a booking agent, business manager, and facilitator than as a performer.

As a performer, her comedy was always a rather gentle and loving satire of her hometown of Centerville, about fifty miles (eighty km) west of Nashville in Hickman County, Tennessee. Her catch phrase was always, "Howdeeee! I'm just so proud to be here!" delivered at what seemed to have been the top of her lungs. Once she was an established star, her audience almost invariably shouted "Howdeeee!" back to her.

Her monologues almost always involved her comical relatives, notably "Uncle Nabob" and "Brother", who was somehow both slow-witted and wise, simultaneously. Her frequent bow-off line to applause was "I love you so much it hurts!" She also sang comic novelty songs, some of which were released as singles, such as "How To Catch A Man."

In her act, she called her hometown Grinder's Switch; it was a real location just outside of Centerville which consisted of little more than the eponymous railroad switch. Those who knew her recognized that the characters were largely based on real residents of Centerville. So much traffic resulted from fans and tourists looking for the hometown she described that the Hickman County Highway Department was finally motivated to change the designation on the "Grinder's Switch" road sign to "Hickman Springs Road". Attempts over the years to develop a Grinder's Switch theme park have proven futile.

Her character was always presented as a man-hungry spinster willing to settle for almost anything in the way of male companionship. In real life, she was happily married for many years to Henry Cannon. They had no children.

In the late 1960s, Mrs. Cannon and African-American gospel singer Mahalia Jackson were convinced to allow their names to be associated with a chain of fried chicken restaurants in competition with Kentucky Fried Chicken by Nashville entrepreneur John Jay Hooker. At first the stock price of this venture soared; later it collapsed amid allegations of accounting irregularities and stock price manipulation. This affair was thoroughly investigated by the U.S. Securities and Exchange Commission. Mrs. Cannon and Ms. Jackson were found to have been completely uninvolved in any alleged wrongdoing, but were considerably embarrassed by the negative publicity surrounding their names. (A small number of these restaurants actually survived into the 1980s in the Middle Tennessee area.)

As noted above, Mrs. Cannon portrayed the "Minnie Pearl" character for many years on the perennial Saturday night television series cornfest Hee Haw, both on the original network and subsequent syndicated versions. This may have been less taxing than it would appear; the program was shot entirely in Nashville and totally out of sequence, so that each performer could record all of his or her appearances for an entire television season in a matter of a few days or parts of days. When asked why the cornball program was so popular, Cannon explained that it took viewers to a place where there was "no war, no cancer."

Her final regular national televison appearances came on Ralph Emery's nightly Nashville Now country-music talk show on the former Nashville Network cable channel. She and Emery performed a weekly feature, "Let Minnie Steal Your Joke," in which viewers could send in jokes for Minnie to read on the show, with prizes for the best joke of the week.

Cannon was fairly influential in the lives of many younger country music artists, taking something of a maternal interest in them, especially Hank Williams, but also many of the younger generation of female singers; she had seen many of the inequities in the treatment of women in business in general, and women in the country music industry in particular, firsthand. She was also a close friend of Paul Reubens. In her later years, she lived in a prestigious Nashville neighborhood next to the Governor's Mansion, where she befriended several of the governors. After surviving breast cancer through aggressive treatments including a double mastectomy and radiation therapy, she became a spokeswoman for the medical center in Nashville where she had been treated and somewhat for cancer survivors in general. She took on this role as herself, Sarah Ophelia Cannon, not desiring the "Minnie Pearl" character to be associated with such misfortune, although a nonprofit group, the Minnie Pearl Cancer Foundation, has been founded in her memory to help fund cancer research. The center where she was treated was later named the Sarah Cannon Cancer Center, and has been expanded to several other hospitals in the Middle Tennessee and Southern Kentucky area. Her name has also been lent to the affiliated Sarah Cannon Research Institute.

Her death at the age of 83 was brought on by complications due to a stroke. During her time in the nursing home, she was visited frequently by numerous country music industry figures, notably Vince Gill and Amy Grant, whose scandalous (as they were both married at the time) romantic relationship is alleged to have begun during joint visits to see her. She is buried at Mt. Hope Cemetery in Franklin, Tennessee.