It's because of their exceptional service, among other factors, according to the results of the 2019 Market Force's Fast Food Market Research Report.
Mark Miller, the vice president of training and development at Chick-fil-A, said the "secret sauce" is all about picking the right operator for each location.
"When we get that operator decision correct, a lot of other decisions take care of themselves," Miller recently told ChristianHeadlines. "Because what we've learned is that they will attract great people to work in their restaurants."
He says Chick-fil-A's corporate office offers operators the chance to be well-led, to have a brighter future and be part of something bigger than yourself – which they can then offer to their employees at each location.
Chick-fil-A's five leadership fundamentals can be summed up in one word: SERVE. See and shape the future; engage and develop others; reinvent constantly; value results and relationships; and embody the values.
"And if you'll look at that closely, you'll realize Jesus had it right 2,000 years ago," Miller said during an 18-minute interview. "When his disciples wanted positions of leadership, he said, 'You don't understand leadership...Those that want to be greatest among you - the greatest leaders - must be willing to become servants.'"
The training expert said they "do it the old fashioned way" with a two-part mission -- to build a leader's skills and heart.
And it doesn't seem to be changing anytime soon as Chick-fil-A's CEO, Dan Cathy, promised his father Truett Cathy to uphold the Christian values and remain closed on Sundays.