As a child, he studied classical piano and learned guitar and organ in Denver, Colorado. As a teenager, he played in local Denver bands. When he left home, he played in touring bands in Texas, where he learned a range of traditional music styles. He then returned to Colorado where he launched the band Head First. In 1979 record producer Keith Olsen invited Tuggle to go to Los Angeles to meet an artist who needed a keyboard player. 
In L.A., Tuggle made numerous professional contacts with bandleaders, which helped to start his touring career. He met Rick Springfield and played with him. He also played keyboards with David Lee Roth in Roth's post-Van Halen career. In 1988, Tuggle co-wrote the top 10 hit single "Just Like Paradise" with David Lee Roth. In 1992, Tuggle was invited by Mick Fleetwood to be a member of the band The Zoo. Tuggle also toured with Steve Lukather from Toto. Tuggle has played with Chris Isaak and Whitesnake.
While Tuggle is known for his onstage keyboard playing for Fleetwood Mac, he was an offstage singer and keyboard player for David Lee Roth in 1986. Unlike most offstage performers, Tuggle was invited onstage with the band for the last few songs of each concert.
Scouting magazine's review of David Lee Roth's album Skyscraper praised Tuggle's co-writing work on what it called the "best tunes" on the album. The review calls Tuggle and Roth's co-written song "Just Like Paradise" "...sexy, sassy, and memorable" and states that Tuggle's keyboard playing "...give[s] the music an extra dimension and make[s] "Paradise" the bounciest cut Roth's been involved in since "Jump"." Rick Springfield's book Late, Late at Night, he states that with his touring band, with "Tim on guitar. Mike Siefret on bass. Brett Tuggle on keyboards", Springfield formed a "special camaraderie" with Tuggle on the road due to their shared interest in "illicit sex" with women.
Ultimate Classic Rock describes the start of David Lee Roth's 1986 Eat 'Em and Smile North American tour. Ultimate Classic Rock states that Roth put together an "...all-star band featuring guitarist Steve Vai, bassist Billy Sheehan and drummer Gregg Bissonette...[and] touring keyboardist Brett Tuggle". Ultimate Classic Rock states that "...the foursome tore through a set list that included an equal blend of Van Halen classics and songs from its new album each night, livening up Roth’s traditional pre-“Ice Cream Man” storytelling introduction with a steel drum solo, and turning bass and guitar virtuosos Sheehan and Vai loose for an extended duel."
- "Brett Tuggle: Yamaha Artists". Yamaha. Retrieved November 5, 2017.
- Wake, Matt (1 February 2016). "Inside the Strange, Hidden World of Offstage Touring Musicians". www.laweekly.com. LA Weekly. Retrieved 21 June 2017.
- Scouting. May 1988 ISSN 0036-9500. Published by Boy Scouts of America, Inc. p. E 11
- Springfield, Rick. Late, Late at Night. Simon and Schuster, 2010
- Wilkening, Matthew (16 August 2016). "30 Years Ago: David Lee Roth Kicks Off His First Solo Tour". ultimateclassicrock.com. Ultimate Classic Rock. Retrieved 24 June 2017.