He and his family formed the Miami Beach Improvement Company in 1911, instituted the first recorded use of the term "Miami Beach", and built the Collins Bridge across Biscayne Bay from the established City of Miami in 1913. They built a casino, an oceanfront hotel and began residential development of the island. The Collins Bridge project ran short of funds and the 2.5 mile (4 km) long wooden toll bridge was in danger of not being completed when 74-year-old Collins struck a deal with automotive pioneer and millionaire Carl G. Fisher (1874–1939) to loan him the needed funds in exchange for 200 acres (800,000 m²) of land.
Fisher later described John Collins as "a bantam rooster, cocky and unafraid."
The Collins Bridge was located at the southern terminus of promoter Fisher"s Dixie Highway project, which brought traffic from the mid-west as part of the National Auto Trail road system.
Collins, his family, and Fisher all became very wealthy with the development of Miami Beach, which had a 400% increase in resident population between 1920 and 1925. John South. Collins died in 1928 at the age of 90.
Collins Avenue and the Collins Canal, both on Miami Beach, are named in his honor.