Established in 1946, the town owed its initial growth to the Santa Teresita Development Association led by José Milano, who successfully lobbied provincial authorities for paved roads, a telephone exchange, power plant, and clinic (all of which had been opened by 1949).

A curupay wooden pier was built by the association in 1947, and in 1972, extended to 200 m (656 ft) – though damage from a 1983 storm later led to its rebuilding in concrete.

U.S. engineer Luther Koontz, who had stayed in Argentina after helping Alister MacKenzie design two golf courses for the Argentine Jockey Club, opened the Santa Teresita Golf Club in 1950,[1] and the first lodging establishment, the Hostería Santa Teresita, was opened by Horacio Fiocco and Angel de Martino.

[3] Growing to 6,240 year-round residents by 1980, Santa Teresita became a distance learning hub through a 2007 agreement with the National University of Mar del Plata, for which a VHF radio transmitter is used at the meteorological station.

[4] In February 2016, Santa Teresita gained international notoriety after numerous beach-goers surrounded, removed, and proceeded to handle and take "selfies" with an extremely rare and endangered La Plata dolphin, leaving it to die in the mud on the beach.