Jack in the Box, Inc. is an American fast-food restaurant chain founded on February 21st, 1951, by Robert O. Peterson in San Diego, California, where it is headquartered.

Robert O. Peterson already owned several successful restaurants when he opened Topsy's Drive-In at 6270 El Cajon Boulevard in San Diego in 1941.

In 1951, Peterson converted the El Cajon Boulevard location into Jack in the Box, a hamburger stand focused on drive-through service.

The Jack in the Box restaurant was conceived as a "modern food machine," designed by La Jolla, California,, master architect Russell Forester.

In the 1970s, Foodmaker led the Jack in the Box chain toward its most prolific growth (television commercials in the early 1970s featured child actor Rodney Allen Rippy) and began to franchise locations.

Jack in the Box began to struggle in the latter part of the decade; its expansion into East Coast markets was cut back, then halted.

[14] Jack in the Box announced that it would no longer compete for McDonald's target customer base of families with young children.

The menu, previously focused on hamburgers led by the flagship Jumbo Jack, became much more diverse, including salads, chicken sandwiches, finger foods, and seasoned Curly Fries (at least two new menu items were introduced per year), at a time when few fast-food operations offered more than standard hamburgers.

At their annual meeting in July 2018, the National Jack in the Box Franchisee Association, which represented the owners of about 2,000 of the chain's 2,240 restaurants, voted "no confidence" in the company's chief executive officer, Leonard "Lenny" Comma, and called for him to resign.

They featured high-quality, cafe-style food, avoiding most of the cheaper fast-food items typically served at Jack in the Box.

Besides tacos, other Americanized foods from ethnic cuisines that Jack in the Box offers include egg rolls, breakfast burritos, and jalapeño poppers.

In Imperial County, California, some locations sell date shakes, reflecting the crop's ubiquity in the region's farms.

[21] Its more recent foray into the deli market was the less-popular Ultimate Club Sandwich, which was initially removed in Arizona due to poor sales and has since been phased out at all locations.

[25] The 4 original Munchie Meals were Spicy Nacho Chicken Sandwich, Sriracha Curly Fry Burger, Stacked Grilled Cheeseburger, and Chick-n-Tater Melt.

[28] In January 2018, the "Food Truck Series" sandwiches were introduced, including the Asian Fried Chicken, Pork Belly BLT, and Prime Rib Cheesesteak.

[33] The restaurant rebounded in popularity in 1994 after a highly successful marketing campaign that featured the fictitious Jack in the Box chairman Jack character (formerly voiced by the campaign's creator Rick Sittig), the mascot who has a ping pong ball-like head, a yellow clown cap, two blue eyes, a pointy black nose, and a linear red smile that changes with his emotions, and is dressed in a business suit.

Jack was reintroduced specifically to signal the new direction the company was taking to refocus and regroup after the 1993 E. coli disaster, discussed below, which threatened the chain's very existence.

In the original spot that debuted in fall 1994, Jack ("through the miracle of plastic surgery", he says as he confidently strides into the office building) reclaims his rightful role as founder and CEO, and apparently as revenge for being blown up in 1980, approaches the closed doors of the Jack in the Box boardroom (a fictionalized version, shown while the aforementioned minimalist theme music from the 1980s Jack in the Box commercials plays), activates a detonation device, and the boardroom explodes in a shower of smoke, wood, and paper.

Often, different types of antenna balls were available during a holiday or major event or themed toward a sports team local to the restaurant.

During the height of the now-defunct XFL, one of the continuing ad series involved a fictitious professional American football team owned by Jack.

The Spicy Crispy Girls concept was used as a model for another successful advertising campaign called the 'Meaty Cheesy Boys' to promote the Ultimate Cheeseburger in 1999-2001 (see below).

The same ad exec featured in a 2001 spot where a medical doctor made exaggerated claims of the benefits of fast food that it would cure baldness, help trim extra pounds, and remove wrinkles.

In 2000, an ad involved a man washed up on a remote island with only a Jack in the Box antenna ball as a companion.

In April 2006, Jack in the Box launched an ad campaign called Bread is Back,[40] taking a stab at the low-carbohydrate diets of recent years.

When faced with a decision, the Jack in the Box figurine in his car tells him to "stick to the classics" and order 30 tacos, implying that he has the "munchies".

Another 600 were reported sick after eating undercooked patties contaminated with fecal material containing the bacteria at a location in Tacoma, Washington, and other parts of the Pacific Northwest.

[50] In September 2010, 40 under-performing company-owned Jack in the Box restaurants located mostly in Texas and the Southeast were set to close.

[57][58] In May 2023, Jack in the Box showed interest in re-entering the Mexican market after a failed first attempt, when it briefly operated there in the early 1990s.

Certain locations (mainly in the San Francisco Bay Area) have a deal where if the 49ers score two touchdowns, customers can purchase a large drink and get a free Jumbo Jack with it the day after the game; the Los Angeles Dodgers have a similar deal in the L.A. metro area and in the Inland Empire if they can strike 10 opposing batters out.