The 28-year-old Frenchman will join the F1 team after the final round of this year's Champ Car season on Dec. 2, Toro Rosso said Friday.
Bourdais is currently leading the U.S.-based series as he bids for an unprecedented fourth consecutive Champ Car title. He drives for the elite Newman/Haas/Lanigan team.
Bourdais has tested three times with Toro Rosso this year.
"It has been a long time coming but here we are," he said. "I would like to thank everyone at Red Bull Racing for believing in me and giving me this long awaited opportunity to race in Formula One."
Bourdais will race alongside Sebastian Vettel, who replaced Scott Speed - the only American driver in F1 - before last weekend's Hungarian Grand Prix.
Bourdais will replace Vitantonio Liuzzi, who has also struggled to make any impact this season. The team has yet to score a point after 11 of 17 races.