With a masters degree in exercise science, Joe Friel was a marathoner and running coach throughout the 1970s and early 1980s. After his first triathlon in 1983 and falling in love with the sport he began coaching multisport athletes becoming one of the first triathlon coaches in the country. The following year he opened a triathlon store in Ft. Collins, Colorado--probably the first in the world. Throughout the 1980s his race management company organized several triathlons in Colorado. He left retail and race management in 1987 to focus on coaching. The athletes he coached for over 30 years ranged from novice to high-performance amateur to professional to Olympian. In 1997, he was a founding member of the USA Triathlon Coaches Association.

He served as co-chair in 1999-2000. In 2000, he attended the Sydney Olympics to assist with team preparation. The following year he was the coach of team USA for the World Triathlon Championships. Throughout the 2000s he was a frequent speaker at USAT coach seminars. He wrote 17 books on training, the most notable being The Triathlete's Training Bible, which is now in its 5th edition and translated into 15 languages. It remains the best-selling book in the world on triathlon training. In 1999, he co-founded TrainingPeaks, online training software for endurance athletes. As an athlete he competed in hundreds of events including national and world championships, was an All-American Age Group Triathlete several times and a USAT-regional multisport champion.

He stopped competing after a bike crash in 2014 restricted range of shoulder movement. He continues to present at triathlon camps and clinics for triathletes and coaches around the world. Joe currently lives and trains in the mountains of northern Arizona and is working on his 18th book--this one for coaches.