"He'd stop cars in front of the restaurant and say, 'Come in and try my restaurant, and if you don't like it, it's on the house,' " said Martinez's daughter Cathy Kreitz.
Martinez kept up that commitment to hospitality; Matt's Famous El Rancho became one of the most popular Mexican restaurants in Austin.
Martinez died Thursday morning of Parkinson's disease. He was 86.
Martinez told the StatesmanAustin American-Statesman in 1984 that his favorite part of owning El Rancho was the people he served.
"I'm here every day to greet them when they walk through the door," he said. "Folks who ate here when they were kids now bring in kids of their own. That's the nicest part."
El Rancho — now at 2613 S. Lamar Blvd. — has served locals and notables, including President Lyndon Johnson and actor Lee Marvin.
Martinez learned the restaurant business from his father, who started one of the first Mexican restaurants in Austin in the 1920s. As a teenager, Martinez sold homemade tamales from a wooden pushcart in downtown Austin to help his father. He also worked in the kitchen of Seton Hospital alongside the Sisters of Charity.
Martinez was a successful boxer, too; he took up the sport as a teenager after being beaten up by a group of bullies in East Austin. Martinez filled burlap sacks with sand and pounded them in his garage to practice. In 1937, he was the Texas Golden Gloves champion.
Martinez boxed around the state until he joined the Army in World War II, where he was a machine gun sergeant and mess hall cook. After the war, Martinez waited tables at some of Austin's top restaurants, including El Charro and Caruso's, before starting his own business with his wife, Janie, in 1952.
Kreitz said her parents did everything in the restaurant at first, from cooking to dish-washing. They served blue-plate lunches initially before serving mostly Tex-Mex, which made the restaurant famous.
Janie did most of the cooking, though Martinez had a talent for adding just the right spices, his family said. He could think up creative twists on old dishes, such as adding pecans and raisins to the chile rellenos, Kreitz said.
Even at the start of the business, his daughter Gloria Reyna said, her parents made the food from scratch and the margaritas with fresh lime. Martinez would often be the first person to greet people at the door. He taught his four children, all of whom worked in the restaurant at some point, to treat every customer like a guest in their home.
"His hospitality was a huge part of its success," Kreitz said. "He just had a great smile and a warm, loving personality."
A Dallas investment firm purchased the property where the original El Rancho sat; the restaurant moved to its site on South Lamar in 1985.
He was inducted into the state's Restaurant Hall of Honor in 1986 and also won Restaurateur of the Year in Austin.
Reyna said he was known as a charitable person who would never turn away people who showed up at the restaurant hungry. Reyna remembered when a beggar approached Martinez on a Tuesday, Martinez's only day off.
"He couldn't stop thinking about the man, so he went to the restaurant and prepared food for him," Reyna said. "He was always that way: so nurturing and caring."