Keselowski began competing in the Busch Series full-time in 2007. He drove the No. 23 Chevrolet Monte Carlo SS for Keith Coleman Racing until the team suspended operations in July. Earlier in June, during the 2007 Truck Series season, Keselowski was tabbed by Germain Racing to replace Ted Musgrave in the No. 9 Team ASE Toyota Tundra for the O'Reilly 200 at Memphis after Musgrave was suspended for an in-race scuffle with another driver at the Milwaukee Mile. Keselowski won his first career pole for the race, and led sixty-two laps, but got turned around by Travis Kvapil as they fought for the lead with ten laps to go. Keselowski wound up finishing 16th. Shortly afterward, Keselowski was called by car owner Dale Earnhardt Jr. to drive the No. 88 United States Navy-sponsored Chevrolet for JR Motorsports for three races, and eventually the rest of the Busch Series season. During the Camping World 300 at California Speedway, Keselowski was involved in an accident involving A. J. Allmendinger and J. J. Yeley. Keselowski was able to climb out of his damaged car but complained of foot pain. He would later be treated and released from Loma Linda University Medical Center and was cleared to race at Richmond the following weekend. Keselowski would close the 2007 season out with five top ten finishes and a twenty-fifth-place finish in points.