In-N-Out Burger was founded in 1948 by Harry and Esther Snyder in Baldwin Park, California. The Snyders opened the first drive-thru hamburger stand, capitalizing on the growing trend of car culture in post-World War II America. With a commitment to providing fresh, high-quality food, they offered a simple menu that featured burgers, fries, and drinks. The emphasis on quality was evident from the start, as they used fresh, never-frozen beef and hand-cut potatoes for their fries. This foundational approach set the stage for what would become a beloved fast-food institution.

Throughout the 1950s and 1960s, In-N-Out expanded steadily, opening new locations in Southern California. The introduction of the "Double-Double" burger in 1963 marked a significant milestone in the chain's history, appealing to customers looking for a heartier meal. Harry Snyder's dedication to maintaining high standards extended to his decision to keep the menu simple and focused, resisting the temptation to diversify with extensive offerings. The company's growth was steady but controlled, ensuring that each new location maintained the same quality and service that customers had come to expect.

After Harry Snyder passed away in 1976, his son, Rich Snyder, took over the family business and continued the legacy of quality and service. Under his leadership, In-N-Out expanded beyond California, opening its first location outside the state in 1992 in Las Vegas, Nevada. The brand's popularity surged in the 1990s and 2000s, with a growing "secret menu" that added to its cult status. Today, In-N-Out operates over 380 locations, primarily in California and the Southwest, while remaining family-owned and committed to its original principles of quality, freshness, and customer satisfaction.