The right-hander was sent from the Philadelphia Phillies to the Dodgers on Friday after Los Angeles claimed him on waivers.
Blanton will join outfielder Shane Victorino, who was traded from Philadelphia to Los Angeles on Tuesday. The last-place Phillies also dealt outfielder Hunter Pence to San Francisco earlier this week.
"It was a little bit of a shock, especially since the trade deadline had passed," Blanton said. "But when you're in trade rumors, you've got to be ready to do whatever. And I was happy if I stayed. At the same time, it will be a new thing, a new adventure to go. And that's always fun."
The 31-year-old Blanton is 8-9 with a 4.59 ERA in 20 starts and one relief appearance. He is making $8.5 million and, like Victorino, can become a free agent after the season.
While the cost-cutting Phillies are preparing for 2013, the Dodgers entered the day a half-game behind San Francisco in the NL West. Blanton bolsters a rotation that includes reigning NL Cy Young Award winner Clayton Kershaw.
"You play for the postseason and a chance to go to the World Series. And they're in a good position," Blanton said. "They have a very good team over there. Pitching against them, I know how good their lineup is. They're in a good position right now. So that's always exciting. They're fighting to win out there, and that's always exciting to be a part of."
Philadelphia will receive a player to be named or cash for Blanton. To fill the roster spot, the Phillies recalled right-hander B.J. Rosenberg from Triple-A Lehigh Valley. Kyle Kendrick was to start against Arizona in Blanton's place Friday night.
Blanton came to Philadelphia after a trade with Oakland in July 2008 and helped the Phillies win their second World Series title. He earned a victory in Game 4 against Tampa Bay and hit a three-run homer off Edwin Jackson.
"I remember the parade, going down Broad Street and all the fans everywhere," Blanton said. "Just the thrill of being able to come to such a baseball city. The fans have been unbelievable the whole time I've been here. I've had an amazing time here."
Blanton was 34-25 with a 4.47 ERA in 100 starts and five relief appearances with the Phillies. Since 2008, Blanton has the fourth-best winning record among all major league starters after the All-Star break at 17-6. He's 38-20 with a 3.83 ERA in 99 games (91 starts) after the break in his career.
Overall, Blanton is 81-71 with a 4.25 ERA in nine seasons. He's 2-0 with a 4.02 ERA in 10 postseason games, including six starts.
The five-time defending NL East champion Phillies have been stuck in last place since June and are dumping salaries. They've trimmed enough off their payroll to avoid having to pay the luxury tax this year.