Frank Day is not afraid to try new things. The Colorado native, who grew up in Chicago, dabbled in running doughnut shops and bartending before moving to Boulder in 1970. Over his five-decades-long career, the founder of Concept Restaurants has operated more than 80 hospitality businesses—including the Hotel Boulderado and Denver’s Stout Street Social and Humboldt Kitchen & Bar—in the Centennial State and beyond. And that doesn’t even count the dozens of outposts of Old Chicago Pizza & Taproom and Rock Bottom Restaurant & Brewery, Front Range–born brands that grew into a separate restaurant group valued at $382 million in 2010, when Day sold it. Since he came back to Colorado, Day has weathered seven economic recessions, bladder cancer, and two attempts at retirement. “Those of us who survive in the restaurant and hotel business, I would term as action junkies,” he says. In honor of Day’s 90th birthday this month, we rounded up highlights from his storied resumé, soon to be padded by a new Boulder brewpub.

1972

Day makes his foray into the Colorado food scene with the Walrus, a basement restaurant equipped with a salad bar in a vintage clawfoot bathtub, on the corner of 11th and Walnut streets in Boulder. Dwindling sales lead him to turn the eatery into a dive bar, which serves booze-happy University of Colorado Boulder students for 46 years before closing in 2018.

1975

Beef jerky, peanuts, and 3.2 Coors Original are the only items on the menu at Walt & Hanks, a tavern Day purchases at 1102 Pearl Street in Boulder. Rowdy regulars spur Day to replace the watering hole with the first Old Chicago, a pizzeria inspired by his love for the Windy City, in 1976.

1980

The Victorian-style Hotel Boulderado joins the Concept Restaurants family. Day was first drawn to the hotel in 1969, when he descended into the Catacombs, the Boulderado’s subterranean bar, during a visit to the Front Range. A cocktail spot called License No. 1 opens in the cult classic’s place in 2014.

1990

Day launches the Walnut Brewery on the Pearl Street Mall; it’s the first business to produce suds on-site in downtown Boulder. The initial success of the brewpub, which eventually shutters in 2017, inspires him to establish more craft-beer-centric concepts, including the Rock Bottom chain, whose first location opens in 1991 on Denver’s 16th Street Mall.

1995

The ChopHouse & Brewery debuts between Coors Field and Union Station. (A Boulder outpost—now Frank’s Chophouse—follows in 2001.) Celebrities such as Celine Dion and John Elway feast on rib-eyes and filets at the white-tablecloth restaurant before Day parts ways with the Denver steak house in 2010.

2014

Steaks, sandwiches, and a sprawling raw bar (where Day can still sometimes be found tucking into platters of freshly shucked oysters) become the draws at Stout Street Social, located across from the Denver Performing Arts Complex.

2022

Boulder Social brewery and pizzeria, Concept Restaurants’ latest endeavor, is slated to open this month off 38th Street and Arapahoe Avenue in the same building that once housed José Muldoon’s, a Tex-Mex spot operated by Day’s group from 1974 to 1990.