Billingsley made his Major League Baseball debut with the Los Angeles Dodgers on June 15, 2006, against the San Diego Padres at Petco Park in San Diego, California. In his debut, Billingsley started on the mound, and pitched 5.1/3 innings and surrendered 6 hits and 2 runs while striking out three. He even knocked in two runs in his first official at-bat (Hit by pitch in his first plate appearance) to help his cause. His debut was considered a success as the Dodgers went on to defeat the Padres 7–3 (although Billingsley did not get credited with the win). Billingsley remained in the starting rotation for the rest of the season, but started 2007 in the bullpen. He pitched well in relief and was returned to the starting rotation on June 21 after season ending surgery placed Jason Schmidt on the disabled list.