Fisher was born in Grady County, Oklahoma, in Tabler (near Chickasha) into a farming family, the son of a Scots-Irish father and part-Choctaw mother and the youngest of four children. He gained the nickname "Shug" (short for sugar) at a young age, which he explained as, "My mama gave it to me 'cause I was such a sweet baby." In 1917, the family moved by covered wagon to Pittsburg County, Oklahoma, near Indianola. Soon thereafter, Fisher was drawn to the mandolin and the fiddle. His father refreshed his own fiddling ability and Fisher learned guitar to back him, and at age 16, he was playing with his father at local square dances. He could not afford a fiddle case and instead protected his instrument with a pillow case tied to the saddle horn.

After watching a Comedian with a traveling Medicine show in 1924, he decided to pursue a career in entertainment. The following year, Fisher, his father, and a friend drove a Ford Model T to California's San Joaquin Valley, where he worked as a fruit-picker and a cable and tool dresser in oil fields. He continued to perform, playing fiddle at social events and square dances. In 1927, he was asked to appear on The Fresno Bee's radio station, KMJ, but only for the publicity. He later said, "publicity was fine, but you can’t eat it...My motto was, pay me something, or I don’t play."

In 1931, Tom Murray, who had recently left the Beverly Hill Billies, offered Fisher a spot with his new group, the Hollywood Hillbillies, based in Los Angeles. Fisher learned to play the bass fiddle with the group and claimed he was one of the first to play the instrument in a country band. The Hillbillies appeared on the Hollywood Breakfast Club radio show and were fairly popular around Los Angeles but had little income to show for it.

In late 1933, Fisher and Ken Carson left the group to join several members of the Beverly Hill Billies who had moved to San Francisco. The original group was the brainchild of the general manager of KPMC-AM, who promoted the members as authentic "hillbilly" Musicians who he'd "discovered." As part of the ruse, the members always adopted hillbilly names, so Fisher became Aaron Judd and Carson was Kaleb Winbush. After a short time, Fisher returned to Los Angeles, appearing on Stuart Hamblen's Covered Wagon Jubilee program.

In 1935, Fisher took an extended road tour with Roy Faulkner, The Lonesome Cowboy, from XERA-AM in Del Rio, Texas. During an appearance in Council Bluffs, Iowa, Fisher was approached by Hugh Cross to join him, under sponsorship of the Georgie Porgie Breakfast Food Company, as an act for WWVA Jamboree. Fisher agreed and the two went to Wheeling, West Virginia. Under the moniker of Hugh and Shug’s Radio Pals, a reflection of their frequent radio appearances, they performed with Mary Ann Vestes and recorded for Decca for four years, enjoying a faithful radio audience.

In 1939, the two moved to Cincinnati, Ohio, where they appeared on WLW-AM's Boone County Jamboree and where Fisher met and married Peggy Summers of Bolivar, Missouri. At the station, he also became friends with a young Merle Travis.

When the U.S. entered World War II in 1941, Fisher returned to Los Angeles to work in defense jobs, primarily at Lockheed Aircraft in Burbank. Art Rush, head of the Hollywood Victory Committee, requested his help arranging entertainment for defense workers during the war.

A member of the John Ford Stock Company, Fisher had an extensive career as a character actor in Western B-movies and feature films starting in 1943. Many of his early roles were as a performer with the Sons of the Pioneers in Roy Rogers' singing Cowboy movies. He was also the voice of Uncle Pecos, an animated mouse, in the 1955 Tom and Jerry short, Pecos Pest, and is uncredited with the guitar improvisation on the cartoon’s version of "Froggie Went A-Courtin".

Fisher left the group in early 1946 when Brady returned from the war. In 1948, Capitol Transcriptions issued the album, Cowboy Jubilee, by Shug Fisher & his Ranchmen Trio. Fisher rejoined the Pioneers in 1949 when Brady left. The highlight of this era came in 1951 when they appeared at Carnegie Hall, making them the first western band to perform there. They would also be the first to play at lavish nightclubs in Las Vegas and starred on Mutual Radio's Lucky U Ranch program. In 1953, Fisher left to join friend Ken Curtis in television and motion pictures but again returned to the Pioneers in 1955, replacing Deuce Spriggens. He left the Pioneers for the last time in 1959, and welcomed the break to "kinda take it easy, and do a lot of hunting and fishing."

Fisher also had many supporting roles during a 27-year television career. From 1955–60, he made regular appearances on ABC-TV’s country music variety show, Ozark Jubilee, as a Comedian and singer. Then he joined Curtis’ first-run syndicated TV adventure series, Ripcord between 1962 and 1963 portraying airplane pilot Charlie Kern. He made 22 appearances on Gunsmoke from 1962–74 in various minor roles, and played Shorty Kellums in 19 episodes of The Beverly Hillbillies from 1969–70. Fisher also appeared repeatedly on Bonanza, The Virginian, Daniel Boone and The Dukes of Hazzard.

Shug Fisher spent his final years living in Studio City, California. He died on March 16, 1984 after a lingering illness, with old friend Ken Curtis by his side in Woodland Hills in Los Angeles. He was buried at Forest Lawn Memorial Park.