Briggs re-joined the Echoes, who had become Dusty Springfield's backing band, and spent a year touring with the British soul diva as well as playing on many of her records during 1965, including most of the album Ev'rything's Coming Up Dusty (released in America as You Don't Have to Say You Love Me) and the U.K. hit single "In The Middle Of Nowhere." It was during this period that he met Brian Auger, the keyboard player and bandleader, and their friendship led to the two being part of the lineup of Steampacket, a group put together by Giorgio Gomelsky as a vehicle for the vocal talents of Julie Driscoll, Rod Stewart, and Long John Baldry. It was out of the breakup of Steampacket that Auger, Driscoll, and Briggs formed Brian Auger & the Trinity. This was Briggs' most challenging and rewarding gig up to that time, and it lasted well into 1966; it also coincided with the birth of a new era in rock music in England, as the group found itself booked alongside a new generation of performers, most notably a young American guitarist named Jimi Hendrix, who was most impressed with Briggs' playing in the Trinity. It was also an era in which Briggs' own fascination with sounds blossomed, as he became familiar with the music of India and of stringed instruments far removed from the electric guitar; at the time, however, he was only able to indulge in his interests in those new sounds privately. In October of 1966, following a show in which the Trinity performed with Johnny Halliday, Briggs was invited to join the new lineup of the Animals being assembled by Eric Burdon, which already included his former bandmate John Weider.

In contrast to most rock musicians of the period, Briggs had not neglected his musical training even after he turned professional, and had mastered the art of musical notation. As a member of Eric Burdon & the Animals, in addition to sharing lead guitar chores with Weider, he was the group's de facto music director and officially credited arranger, coming up with horn charts and adding alto saxophone and other reed parts to their songs. This version of the Animals was far removed from the blues and R&B-based material of the 1964-1965 version of the group; steeped in a bold psychedelic sound, their debut single, "When I Was Young," opened with a virtuoso pyrotechnic guitar display by Briggs. The group later attempted several daring conceptual works and songs of sufficient complexity to challenge Briggs' musical skills; one of the highlights was the single "Sky Pilot," for which Briggs mixed the sound of the Royal Scots Guards bagpipes and drums with that of the group. During this period, he achieved some of the greatest exposure he ever had in the music press, when Jimi Hendrix, by then a superstar guitarist, named Briggs as one of his favorite guitarists, alongside Eric Clapton and Jeff Beck.

For three years, Briggs locked horns with official producer Tom Wilson (before actually supplanting him), and juggled Burdon's ego and the group's seemingly perpetual lack of preparedness when it came to cutting albums. The resulting LPs, Winds of Change and The Twain Shall Meet, weren't really representative of the group's sound on-stage, but they had interesting moments. For Briggs, high points such as the Monterey Pop Festival were worth the constant touring, the ego battles with Burdon, and the creative treadmill on which he sometimes felt caught.

By the time of the Every One of Us LP in 1968, however, he was ready to leave the group. He felt, after three albums, that the group would never get their act together properly in the studio, beyond the one-off single every year or so that kept them getting good gigs and their albums rising into the Top 200 in America. Additionally, he was feeling cheated when it came to monetary reward for his work; any royalties he was due were eaten up by a confusing array of contracts involving various managers and publishers. Burdon obliged by simultaneously firing Briggs and bassist Danny McCulloch; their replacement was Andy Summers, an old bandmate of Animals keyboard player Zoot Money and later one third of the Police. Briggs had already started a parallel career as a producer for Giorgio Gomelsky's independent Marmalade label, and he hoped to extend that to producing full-time. He was hired as a staff producer at Capitol Records in Los Angeles and during six months there worked on Danny McCulloch's solo album, Wings of a Man; Welcome to My Head, by Zoot Money; It's All in Your Head, by ex-Animals guitarist Hilton Valentine; and Close, by ex-Music Machine singer Sean Bonniwell.

Briggs later began immersing himself in Eastern religion and meditation. By 1970, he was back in London teaching Yoga, and he later became closely involved with the Sikh community. Briggs became a Sikh and took the name Vikram Singh Khalsa, under which he recorded several albums of Indian music. He also periodically returned to playing guitar in a rock context, occasionally with Jerry Garcia and other members of the Grateful Dead and like-minded musicians, and even with his old bandmates from the Animals. He has since taken the name Antion, in response to a change in his consciousness, and moved to Hawaii where, among other musical and spiritual endeavors, he and his wife Elandra began learning traditional Hawaiian chant. Amid all of the changes, Antion still acknowledges his past history and its relevance, including his work with Dusty Springfield and the Animals. Although his incarnation of the latter is usually overlooked by rock historians, and little of their music beyond a handful of hits has remained in print, his contribution to their music and the field of psychedelic music looms large for its quality.