Harold Butler and Richard Jezak founded Denny's in 1953.
The first Danny's Donuts, the precursor to Denny's, opened in Lakewood, California, in 1954.
In 1956, after Richard Jezak left the company, Harold Butler shifted the concept from a donut shop to a 24-hour coffee shop, renaming it Danny's Coffee Shops.
To avoid confusion with a Los Angeles chain, Danny's Coffee Shops was renamed Denny's Coffee Shops in 1959.
Denny's began franchising in 1963, leading to most Denny's restaurants becoming franchisee-owned.
Architects Armet & Davis designed a new prototype building for Danny's Coffee Shops in 1965, featuring a zigzag shingled roof.
The first Denny's restaurant in Japan opened on April 27, 1974, on the first floor of the Ito-Yokado in Kamiōoka, Yokohama.
Denny's introduced the Grand Slam breakfast in 1977.
By 1981, Denny's had expanded to over 1,000 restaurants across all 50 US states.
Denny's opened its first restaurant in Australia in December 1982 in Forest Hill, Melbourne.
In 1984, Denny's entered into a licensing agreement with a subsidiary of Seven & I Holdings to operate Denny's restaurants in Japan.
Trans World Corporation (TW Corporation) acquired Denny's in 1987.
All but six Denny's restaurants closed for the first time ever on Christmas 1988.
Denny's moved its main offices from La Mirada, California, to Irvine, California, in 1989, later relocating to Spartanburg, South Carolina, after being acquired by Trans World Corporation.
The Australian Denny's franchise was sold in 1989 and closed shortly after due to changing consumer tastes.
Denny's started offering a free meal to customers on their birthday in 1990, a promotion that lasted until 1996.
In 1991, a Denny's in San Jose, California, refused to serve a group of black teenagers unless they agreed to pay for their meal in advance.
Private equity firm Kohlberg Kravis Roberts acquired a 47% interest in TW Corporation, later known as The Flagstar Companies, in 1992.
In 1993, a Denny's restaurant in Annapolis, Maryland, was the site of a discriminatory incident where six black Secret Service agents experienced significant delays in service while their white counterparts were seated promptly.
Denny's became the largest corporate sponsor of Save the Children, a national charity, in 1994.
In 1994, Denny's began renovating its stores with a lighter color scheme and briefly partnered with Baskin-Robbins to serve ice cream at select locations.
In 1994, Denny's reached a $54.4 million settlement in a class action lawsuit. The lawsuit alleged that the restaurant chain systematically discriminated against black customers by refusing service, imposing longer wait times, or requiring higher payments compared to white patrons. This marked the largest settlement under federal public accommodation laws at that time.
In 1995, a black customer at a Denny's in Sacramento, California, reported being asked to pay for his meal upfront. The waitress explained that this request stemmed from a previous incident where black customers had left without paying.
Denny's discontinued its free birthday meal promotion in 1996 due to abuse of the offer.
The first Denny's Classic Diner, designed to resemble classic 1950s diners, opened in Fort Myers, Florida, in May 1997.
Flagstar, Denny's parent company, filed for Chapter 11 bankruptcy on July 12, 1997.
In 1997, six Asian-American students from Syracuse University experienced severe discrimination at a local Denny's. They endured prolonged wait times while white patrons were served promptly. After complaining, they were forced to leave by security and subsequently physically attacked by a group of white men outside the restaurant.
Following the discrimination lawsuits and settlements, Denny's implemented a racial sensitivity training program for its employees and featured African-Americans in its advertising campaigns. These efforts led to Fortune magazine recognizing Denny's as the "Best Company for Minorities" in 2001.
In October 2004, Denny's was featured in a Dateline NBC segment called "Dirty Dining," which examined health inspection records of popular restaurant chains, and Denny's had the fewest violations.
Denny's was recognized for its diversity efforts by Black Enterprise magazine, ranking first on their "Best 40 Companies for Diversity" list in both 2006 and 2007.
Denny's continued its commitment to diversity and inclusion, earning the top spot on Black Enterprise's "Best 40 Companies for Diversity" list for the second consecutive year.
Denny's began transitioning to using cage-free eggs in 2008 as part of its animal welfare efforts in collaboration with the Humane Society of the United States.
Since 2009, Denny's has offered a free Birthday Build-Your-Own Slam to customers on their birthday.
Denny's expanded its US presence in July 2010 by opening locations inside Pilot Flying J truck stops.
Denny's opened its first airport location and its first in the Dominican Republic at Las Américas International Airport in June 2012.
Denny's announced a deal in July 2012 to open 50 restaurants in southern China, though the deal was canceled before any openings.
In 2012, Denny's made a public commitment to work with its suppliers and transition away from using gestation crates for pigs. However, this commitment was later removed.
Denny's planned to begin opening restaurants in China in 2013 as part of a franchise agreement, but the expansion was canceled.
Denny's opened its first New York City location in Lower Manhattan on August 29, 2014, featuring a more upscale design and alcohol service.
In 2014, a Denny's location in Deming, New Mexico, faced allegations of discrimination from an LGBTQ+ group. The group alleged that staff used homophobic slurs and refused service to a group of gay, lesbian, and transgender individuals.
The first Denny's restaurant in Japan closed on March 20, 2017, due to the demolition of the Ito-Yokado building where it was located.
In June 2017, eight Denny's restaurants in Colorado, including those in Colorado Springs and Pueblo, were abruptly shut down. The closures were attributed to the franchise owner's failure to pay approximately $200,000 in back taxes and over $30,000 in sales tax. The franchisee's actions left numerous employees jobless and without warning, and the franchisee fled the state.
In November 2017, Denny's announced plans to open its first UK restaurant in Swansea.
Denny's opened its first UK restaurant in Swansea in December 2017, initially serving homeless people on Christmas Day before opening to the public.
In 2017, a Denny's in Vancouver, British Columbia, was accused of racial discrimination when staff allegedly made an Indigenous woman pay for her meal before it was served. After the customer's departure, the staff called the police alleging she possessed a weapon, further escalating the situation.
The upscale Denny's location in Lower Manhattan closed in January 2018.
At the end of 2023, Denny's had 1,602 restaurants globally, with the majority located in the United States.
The global animal rights organization, Animal Equality, initiated a public information campaign in 2023 to highlight Denny's continued use of gestation crates for pigs within their supply chain.
On January 31, 2024, a Denny's location in Oakland, California, which had been in operation for 54 years, permanently closed its doors. The company attributed the closure to concerns about the "safety and well-being" of both customers and employees.
In 2024, the Humane Society of the United States submitted a shareholder proposal urging Denny's to reinstate a deadline for eliminating gestation crates from their supply chain.