The name Justin has its origins in the Latin name Justinus, which was derived from the word "justus" meaning "just" or "fair". It emerged during the Roman era and was initially used as a surname or cognomen.

The earliest known record of the name Justin dates back to the 2nd century AD, when it was borne by several early Christian saints and martyrs. One of the most notable was Justin Martyr, a philosopher and apologist who lived from around 100-165 AD and was one of the first non-Jewish writers to defend Christianity.

During the Middle Ages, the name Justin remained relatively uncommon but continued to be used occasionally in various parts of Europe, particularly in regions influenced by Latin culture and the Catholic Church. Notable bearers from this period include Justin of Siponto, an Italian bishop and saint who lived in the 11th century.

The name gained broader popularity during the Renaissance and Enlightenment periods, when classical names and ideals experienced a resurgence. Justin Martyr, regarded as one of the earliest Christian philosophers, became an important figure for scholars and theologians of the time.

Some notable historical figures named Justin include Justin I, a Byzantine emperor who ruled from 518 to 527 AD, and Justin II, who was emperor from 565 to 578 AD. Another prominent bearer was Justin the Gnostic, a 2nd-century Christian philosopher and writer.

In the modern era, several notable individuals have carried the name Justin. These include Justin Trudeau, the current Prime Minister of Canada, born in 1971; Justin Timberlake, the American singer and actor born in 1981; and Justin Bieber, the Canadian singer born in 1994.

Other notable Justins throughout history include Justin Gatlin, the American sprinter and Olympic gold medalist born in 1982; Justin Verlander, the American baseball pitcher born in 1983; and Justin Rose, the English professional golfer born in 1980.