Since Lynsi Snyder took over as the California-based company’s president in 2010, its size has nearly doubled, from 230 stores in four states to 402 in eight.Ms. Snyder-Ellingson is the only grandchild of Harry and Esther Snyder who founded In-N-Out in 1948. She gained full control of the burger chain when she turned 35 and is worth an estimated $3.6 billion, according to Forbes. When Harry and Esther Snyder opened their first hamburger stand after World War II, their business plan was to sell a few simple, inexpensive menu items made from the best, freshest ingredients they could obtain, and to prepare them meticulously by hand, so that they tasted as good as possible. The Snyders’ emphasis on quality and value was combined with slow, cautious expansion in which the parent company kept control of all the restaurants bearing its name, rather than selling franchises. When Harry Snyder died in 1976 and control of the company passed to his son and Lynsi’s uncle, Rich Snyder, the chain had just 18 restaurants, all in California. Snyder, who inherited control of In‑N‑Out in 2006 when her grandmother died, and ascended to the corporate presidency in 2010. She’s the daughter of Harry and Esther Snyder’s eldest son, Guy, a flamboyant, fun-loving nonconformist--passed over for the company presidency after Harry’s death in 1976. The job went to his younger but more conservative brother, Rich. In 1993, when Lynsi was 11, Rich Snyder and four others were killed in the fiery crash of a private jet near John Wayne Airport. As a result, her father Guy was elevated to company chairman, and her grandmother took over as president. Guy Snyder died at age 48, of an accidental overdose of the painkiller hydrocodone, leaving behind Lynsi and her mother, Lynda Lou Perkins (née Wilson), whom Guy had met in 1979 while staying at one of the family’s vacation homes in Hermosa Beach. Lynda was seven years older than Guy, with two pre-teen daughters from a previous marriage. After her dad died in 1999, Lynsi married at age 18, a union with a young man from her Northern California hometown that lasted only two years. In 2005, she married Richard Martinez, an In‑N‑Out staffer. Though the two eventually split, she continues to work with a missionary-training charity in which she and Martinez, who is now a pastor, became immersed.