Turner's status seemed to be in question after the Chargers went 8-8 this season and missed the playoffs for a second consecutive year.
But Chargers president Dean Spanos officially ended speculation with a statement.
"Bottom line, I believe these two men give us the best chance to get back to the playoffs," Spanos said. "A.J. Smith is the best man to improve our roster, and Norv Turner is the best man to lead that roster on the field."
Turner became San Diego's head coach in 2007 and led the team to an 11-5 mark and a trip to the AFC Championship Game.
The Chargers went 8-8 and 13-3 over the next two years, respectively, but lost in the divisional round of the playoffs both times.
Following a 9-7 record in 2010, San Diego got off to a 4-1 start in 2011. A six-game losing streak followed and the team was never able to recover.
"As we've seen throughout Norv's tenure and particularly this past season, the players believe in him, respect him and play hard for him," Spanos said. "When we went through that tough stretch, no one quit. The team kept playing hard, and that's a tribute to Norv's leadership and the respect the players have for him."
The Chargers have an impressive 52-34 overall record (including 3-3 in the postseason) under Turner, the highest overall winning percentage in franchise history (.605).
Turner's tenure in San Diego includes an impressive 21-3 record in December and January.
The Chargers have won 88 games and five AFC West titles under Smith, who has been general manager since 2003.
"We all have our quirks and faults, but I want A.J. and Norv on my side. They are the right men to help us win a championship," Spanos said.