Born in 1903 in an area known as the Barrens near the small southern town of Lamb, Kentucky, Cynthia May Carver (later known as Cousin Emmy) was the youngest of eight children. Her father was a sharecropper who raised tobacco and Cynthia May began working in the fields as a child. From as far back as anyone remembers, Cynthia May entertained her family in the fields by singing and creating musical skits. A self-described "natural show-off," she began teaching herself to play any musical instrument she could get her hands on, beginning on fiddle and banjo. She grew up hearing the traditional ballads and fiddle tunes of rural Kentucky and with only two years of formal education, allegedly learned how to read by studying Sears-Roebuck mail order catalogues. During her teen years, two of her cousins, Noble “Bozo” Carver and Warner Carver had a popular string band and in 1927 they became one of the first regional groups to make a record. Soon they were making a decent living performing live and on a radio station broadcasting out of Kansas City and invited Cynthia May to join them. In 1935, she returned to Kentucky and her career and recognition as a musician took another leap forward when she became banjoist with Frankie Moore's Log Cabin Boys. It was Moore who named her Cousin Emmy and he had his own live radio show on WHAS out of Louisville, which increased in popularity upon Cousin Emmy's arrival. By this point, Cousin Emmy had become proficient at numerous other instruments, including guitar, piano, ukelele, harmonica, and more unusual items like jaw harp and singing hand saw. Her brash personality and raw musical talent led to her own radio show on WHAS, which gained her an even larger following by 1936. That same year she became the first woman to win the National Old Fiddlers contest.

Over the course of the next decade, Cousin Emmy would become one of the most popular radio stars of the era, performing around the South and Midwest like an unstoppable cyclone. One of the first women in country music to establish her own performing troupe, which included four other women musicians dubbed "The Kin Folks," Cousin Emmy was a true pioneer of roots music, traveling around the country in her Cadillac-one of her trademarks. With a vocal style likened to Loretta Lynn and Ethel Merman combined and a hard, fast-driving banjo style (now known as "frailing"), she strutted and danced across stage after stage, electrifying audiences everywhere she went. While performing on radio station WWVA in Wheeling, West Virginia, she caught the attention of Louis Jones (AKA Grandpa Jones) who would become a close friend, adopting her banjo style and continue to champion Cousin Emmy and her music for many years to come.

Cousin Emmy finally got her first opportunity to record in 1940, when folklorist Alan Lomax helped land her a deal with Decca. The album, Kentucky Mountain Ballads, would contain her one and only hit, an original banjo tune called "Ruby (Are You Mad At Your Man)," a song that would become a bluegrass standard when it was rerecorded by the Osbourne Brothers, becoming their signature song. She seldom recorded again, but it didn't matter as only a fraction of her powerhouse, in-your-face style of entertainment could be translated to recordings of that era. As things turned out, she didn't need to release records as the following year her biggest break arrived when she landed a spot on KMOX in St. Louis. A 50,000-watt CBS station with 2.5 million steady listeners, KMOX truly launched Cousin Emmy directly into homes all over North America. Her undeniable talent and dynamic style surged over the airwaves, and her mountain music captivated listeners from Canada to Guadalcanal, influencing and inspiring countless country, folk, and bluegrass artists to follow. Her popularity became so great that she even merited an article in Time Magazine, an unheard of achievement for any roots musician in 1943. Throughout the decade, Cousin Emmy remained one of America's most beloved musician-entertainers.

As the popularity of live radio died out during the 1950s, Cousin Emmy moved to Los Angeles, where she continued performing and even took on a nonmusical role in the 1955 movie, The Second Greatest Sex. Following an early 1960s performance at Disneyland, she was approached by members of the New Lost City Ramblers, a young string band that had become quite popular during the folk revival. With their help and encouragement, Cousin Emmy made a comeback, performing at Newport and on Pete Seeger's television program, again becoming quite popular through her travels on the folk revival circuit. She also recorded an album with the Ramblers that introduced her to a whole new generation of fans.