Both sons were musically inclined and encouraged by their parents. At age nine, Gallagher received his first guitar from them, and began to teach himself to play, performing at first at minor functions. After winning a talent contest when he was twelve, Gallagher began performing in his adolescence with both his acoustic guitar, and an electric guitar he bought with his prize money. However, it was his purchase three years later, of a 1961 Fender Stratocaster for £100 that became his primary instrument most associated with him for the span of his lifetime. Initially playing skiffle, after hearing Lonnie Donegan on the radio, who frequently covered blues and folk performers from the United States, Gallagher began experimenting with folk, blues, and rock music. Unable to find or afford record albums, Gallagher stayed up late to hear Radio Luxembourg and AFN where the radio brought him his only exposure to the actual songwriters and musicians whose music moved him most. Influences he discovered, and cited as he progressed, that included Woody Guthrie, Big Bill Broonzy, and Ledbelly. Initially, Gallagher struck out after just an acoustic sound.
Singing and later using a brace for his harmonica, Gallagher learned to play slide guitar, using a plectrum and metal slide on his smallest finger. Several years later he also became proficient on the alto saxophone, bass, mandolin, banjo and the coral sitar, utilizing a glass slide made from an American Coricidian bottle, on his electric guitars (as did many contemporaries, such as Duane Allman), instead of the metal slide. Gallagher stated that his ability to track down the actual original songwriters and performers of blues numbers which he'd first heard performed by others like Lonnie Donegan took time and dedication, and had not been easy. Having no role models in Cork, Ireland, he continued to rely entirely on radio programs and television. Occasionally, the jazz programs from the BBC would play some blues numbers, and he was able to slowly find songbooks for guitar, where he found the names of the actual composers of blues pieces. While still in school, playing songs by Buddy Holly and Eddie Cochran, he discovered his greatest influence in Muddy Waters. By his mid-teens, he began experimenting heavily with different blues styles.
Gallagher began playing after school with Irish showbands, while still a young teenager. In 1963, he joined one named Fontana, a sextet playing the popular hit songs of the day. The band toured Ireland and the United Kingdom, giving him the opportunity to acquire songbooks for the guitar, where he found the names of the actual composers of blues songs, in addition to earning the money for the payments that were due on his Stratocaster guitar. Gallagher began to influence the band's repertoire, beginning its transition from popular music, skirting along some of Chuck Berry's songs and by 1965, he'd successfully molded Fontana into "The Impact", with a change in their lineup into an R&B group which played gigs in Ireland and Spain, finally disbanding in London. Rory left with the bassist and drummer to perform as a trio in Hamburg, Germany. In 1966, Gallagher returned to Ireland and, experimenting with other musicians back home in Cork, decided to form his own band.
Having completed a musical apprenticeship in the showbands, and influenced by the increasing popularity of beat groups during the early 1960s, Gallagher formed "The Taste", which was later renamed simply, "Taste", a blues and R&B trio, in 1966. Initially, the band was composed of Gallagher and two Cork musicians, Norman Damery and Eric Kitteringham, however, by 1967, they were replaced with two musicians from Belfast, featuring Gallagher on guitar and vocals, drummer John Wilson, and bassist Richard McCracken. Performing extensively in the United Kingdom, the group played regularly at the Marquee Club, supporting both Cream at their Royal Albert Hall farewell concert, and the blues supergroup, Blind Faith, on a tour of North America. Managed by Eddie Kennedy, the trio released the albums Taste and On The Boards, and two live recordings, Live At Montreux and Live At The Isle Of Wight. The latter appeared long after the band's break-up, which occurred shortly after their appearance at the 1970 Isle of Wight Festival.
After the break-up of Taste, Gallagher toured under his own name, hiring former Deep Joy bass player Gerry McAvoy to play on Gallagher's eponymous debut album, Rory Gallagher. It was the beginning of a twenty year musical relationship between Gallagher and McAvoy; the other band member was drummer Wilgar Campbell. The 1970s were Gallagher's most prolific period. He produced ten albums in that decade, including two live albums, Live In Europe and Irish Tour '74. 1972 saw the release of his album, Deuce. In the same year he was voted Melody Maker's International Top Musician of the Year, ahead of Eric Clapton.
Gallagher played and recorded what he said was "in me all the time, and not just something I turn on ...". Though he sold over thirty million albums world wide, it was his marathon live performances that won him greatest acclaim. He is documented in the 1974 film Irish Tour '74, directed by Tony Palmer. During the heightened periods of political unrest in Ireland, as other artists were warned not to tour, Gallagher was resolute about touring Ireland at the least, once a year, during his career, willing him the dedication of thousands of fans, and in the process, becoming a role model for other aspiring young Irish musicians. Gallagher himself admitted in several interviews that at first there weren't really any international Irish acts until Van Morrison, Gallagher, and slightly later, Phil Lynott and Thin Lizzy grew popular during the 1970s.
The line-up which included Rod De'Ath on drums and Lou Martin on keyboards, performed together between 1973 and 1978, however, he eventually dropped down to just bass, guitar and drums, and his act became a power trio. Other releases from that period include Against the Grain, Calling Card, Photo-Finish and Top Priority. Gerry McAvoy has stated that the Gallagher band performed several TV and radio shows across Europe, including Beat-Club in Bremen, Germany and the Old Grey Whistle Test. Along with Little Feat and Roger McGuinn, Gallagher performed the first Rockpalast live concert at the Grugahalle, Essen, Germany in 1977.
Gallagher collaborated with Jerry Lee Lewis and Muddy Waters on their respective London Sessions in the mid 1970s. He played on Lonnie Donegan's final album. He was David Coverdale's second choice (after Jeff Beck) to replace Ritchie Blackmore in Deep Purple. Gallagher chose to perform in his own band.
In the 1980s he continued recording, producing Jinx, Defender, and Fresh Evidence. After Fresh Evidence, he embarked on a tour of the United States. In addition he played with Box of Frogs which was a band formed in 1983 by former members of The Yardbirds, who released their first album in 1984. Former Yardbirds guitarists Jeff Beck and Jimmy Page also guested on their first and second albums respectively.
Gallagher was always associated with his well-worn sunburst 1961 Stratocaster (Serial Number 64351), which his brother Donal has officially retired. It was reputedly the first in Ireland, and was ordered from Fender by Jim Connolly, a showband member performing with The Irish Showband. Connolly ordered a cherry red Stratocaster through a music shop in Cork. When Fender shipped a sunburst Stratocaster instead, it went on sale as a second-hand instrument, which Gallagher bought for just shy of £100 at Crowley's Music Store on Cork's McCurtain Street. The guitar was extensively modified by Gallagher. The tuning pegs, for a start, are odd (5 Sperzel pegs and one Gotoh), and all of these have been found to be replacements. Secondly, it is thought that the nut has been replaced and interchanged a number of times. Thirdly, the scratchplate was changed during Gallagher's time with Taste. Another change was made regarding the pickups, of which none are original. The final modification was that of the wiring: Gallagher disconnected the bottom tone pot and rewired it so he had just a master tone control along with the master volume control. He also installed a 5-way selector switch in place of the vintage 3-way one. The most notable effect that years of touring have had is the almost complete removal of the guitar's original sunburst finish, due to Gallaghers rare blood type which caused his sweat to be unusually acidic. Although the Strat was left abandoned in a ditch, in the rain, for days after being stolen, this isn't believed to have caused any of the effect. All of the wear is caused by playing, not misuse. It also had a period of time of having a replacement neck, with the original bowing due to the amount of moisture it absorbed during continuous touring. The neck was taken off the strat and left to settle, and was eventually reunited with the Strat after returning to its correct shape. Other quirks include a 'hump' in the scratch plate which moves the neck pickup closer to the neck on the bass side and a replacement of all of the pickups, though this replacement was due to damage rather than a perception of a tonal inadequacy. One final point of interest is that one of the clay double-dot inlays at the 12th fret fell out and was replaced with a plastic one, which is why it is whiter than the other clay inlays.