There are many modern day uses for the chronograph, but the original use for this device, and also the reason it was invented, was to please King Louis XVIII in 1821. The King greatly enjoyed watching horse races, but wanted to know exactly how long each race lasted, so Nicolas Mathieu Rieussec was hired to invent a contraption that would do the job. As a result, he created the first ever commercialized chronograph.
The first chronograph was invented by Louis Moinet in 1816, although it was Nicolas Mathieu Rieussec who developed the first marketed chronograph and the term 'chronograph' dates all the way back to 1776 when a man named Jean-Moyes Pouzait came up with an idea for a device that could record the time of flight of projectiles. The term, Chronograph comes from the Greek word for "chronos" and "graph", which is translated to time and writing. Early versions of the chronograph are the only ones that actually used any "writing". They would write on the dial with a small pen attached to the index; the length of the pen mark would indicate how much time has elapsed. This vastly differs from the modern day chronograph, where the stopwatch feature is electronic or digital. This caused there to be a push to change the name to chronoscope.
In 1844 there was a breakthrough with the chronograph; unlike the constantly moving needle in the original chronograph, Adolphe Nicole's updated version of the chronograph was the first to include the re-setting feature, which now allowed successive measurements.
The automatic chronograph was invented in 1969 by the watch companies Heuer, Breitling, and Hamilton, and movement specialist Dubois Depraz, who were all in a partnership. They developed this technology secretly, in hopes that other companies would not see their efforts and beat them to the patent. It was in Geneva and in New York that this partnership shared the first automatic chronograph with the world on March 3, 1969. These first automatic chronographs were labeled "Chrono-matic".
Many people confuse chronograph with a chronometer, but in order to be labeled a chronometer the watch must be certified by the COSC, the official Swiss Chronometer testing institute. Many companies sell their own styles of chronographs. While today most chronographs are in the form of wrist watches, in the early 19th century pocket chronographs were very popular.