The Chargers would strike back in the second quarter as running back LaDainian Tomlinson got a 1-yard touchdown run. In the first quarter, San Diego trailed early as Raiders running back Michael Bush got a 4-yard touchdown run. The Chargers began their season at Oakland–Alameda County Coliseum for a Week 1 AFL Legacy duel with their AFC West rival, the Oakland Raiders, in the second game of an MNF doubleheader. Note: Intra-division opponents are in bold text.
The Chargers are also expected to be in the hunt for a running back to eventually replace Tomlinson, who despite past excellence has faced more frequent injuries and declining production as he ages. Commonly noted areas of need include the safety positions, the right side of the offensive line, and inside linebacker. Many have speculated as to who the Chargers are likely to target early in the 2009 NFL Draft. Also, this was the end of an era as future Hall of Fame running back LaDainian Tomlinson joined the New York Jets following the season, ending his 9-year tenure as a Charger.
It was also Norv Turner's best regular season record as head coach. They finished the regular season with a 13–3 record, the second best winning percentage in franchise history but were upset in the Divisional Playoffs by the New York Jets. The Chargers improved upon their regular season record of 8–8 in 2008 and won their division for the fourth straight year and fifth time in six seasons. The 2009 season was the San Diego Chargers' 40th in the NFL and their 50th since becoming founding members of the American Football League.