Power began racing in 2000 in Formula support series. He also raced in the British Formula 3 Championship with Diamond Racing and Fortec Motorsport as well as running a test with Minardi in Formula One.
He made his Champ Car debut in Australia in 2005 for Team Australia and raced the final two races of the season for the team.
In 2006, he ran the full season with Team Australia, scoring three top fives and nine top 10s en route to finishing sixth in the championship standings. Also, he captured the pole for his home event, the Lexmark Indy 300 on the Streets of Surfers Paradise, Queensland, Australia.
In 2007, Power finished the Champ Car season in fourth after winning two races at Las Vegas and Toronto and finishing in the top five eight times and top 10 nine times.
Power moved over to the IndyCar Series when Champ Car folded. He raced for KV Racing Technology in his first year of racing in the IndyCar Series and finished 12th in the points. His season was highlighted by a win in the last Champ Car sanctioned event on the Streets of Long Beach. He also recorded five top-10 finishes, including eighth and fifth-place finishes to close out the season.