Short answers, pulled from the story.
Stanislav Yevgrafovich Petrov was born on the 7th of September 1939 to a Russian family near Vladivostok. His father flew fighter aircraft during World War II while his mother worked as a nurse in their hometown.
On the 26th of September 1983 Stanislav Petrov declared the Oko nuclear early-warning system's indication of five incoming missiles a false alarm despite protocol requiring immediate reporting. Later analysis showed no missiles were approaching because sunlight aligned with high-altitude clouds above North Dakota triggering an error in the Molniya orbits of the satellites.
Stanislav Petrov underwent intense questioning by his superiors and received no reward because the incident embarrassed his superiors and scientists responsible for the missile detection system bugs. He was reassigned to a less sensitive post and took early retirement though he emphasized he was not forced out of the army before suffering a nervous breakdown shortly after leaving service.
The incident became known publicly in 1998 upon the publication of General Yury Votintsev's memoirs. Stanislav Petrov received the World Citizen Award from the Association of World Citizens on the 21st of May 2004 and the Dresden Peace Prize in Dresden Germany on the 17th of February 2013.
Various internet communities commemorate the 26th of September as Stanislav Petrov day following Eliezer Yudkowsky's blog post highlighting the story. The post urged people wherever they are whatever they were doing to take a minute not to destroy the world due to the potential nuclear war that might have occurred by accident on the 26th of September 1983.