Growth in Daytona Beach truly began when the St. Johns & Halifax River Railway, which was later purchased by Henry Flagler in 1889, was extended to the town. Flagler was instrumental in developing most of the Florida east coast. As early as 1902, Daytona Beach began to earn a nickname as "The Birthplace of Speed", when inventors would come to the wide, compacted sand beaches to test their new vehicles. Many of the early land speed records were set on Ormund Beach in Daytona Beach.

Daytona Beach became a city in 1926 when the towns of Daytona, Daytona Beach and Seabreeze merged. The city continued its association with speed with the founding of the National Association of Stock Car Auto Racing and remains its headquarters. In 1959, William France built the Daytona International Speedway to replace the road course that had been used for racing previously. The Speedway is host to the Daytona 500 and other NASCAR events, as well as other car, truck, and motorcycle races.

As early as the 1920's, Daytona Beach had earned another nickname, "The World's Most Famous Beach." Today, Daytona Beach is known world wide for its annual Spring Break events, drawing colleges students from many nations to enjoy the beach. For years, Daytona Beach drew more Spring Break visitors than any other destination in the world, but other locations have slowly passed it for that distinction. Daytona Beach is also home of the largest motorcycle gathering in the world, Bike Week. Held in early March, bike enthusiast from around the world gather here each year to see new and unusual motorcycles and each other.