Newt Scamander leaves Hogwarts

Newt Scamander leaves Hogwarts under a cloud, having been accused of endangering students. Albus Dumbledore, then a teacher at Hogwarts, argued against his expulsion (WFT). Soon after, Newt begins working for the Ministry of Magic (FB).

Timeline Notes
We don't know the actual year that Scamander was expelled, but it would have been before 1915.

Notes
One of the companion books published along with the release of the film states that Newt's close friend Leta Lestrange was responsible for the experiment which went wrong and endangered other students, and that Newt chose to take the blame for it.

Newt Scamander starts working in the Office of House-Elf Relocation

"Tedious in the extreme"
-- Newt Scamander describing his time in the Office of House-Elf Relocation (FB)

After leaving Hogwarts, Newt Scamander takes a job in the Department for the Regulation and Control of Magical Creatures’ Office of House-Elf Relocation. He finds it extremely boring. Two years later, he is transferred to the Beast Division (FB).

July 28th, 1914
World War I begins

World War I was a vast military conflict fought between the Allies, a group of nations including Britain, France, and the United States, and the Central Powers, which consisted principally of Germany and Austria-Hungary. The war originated in Europe due to a web of alliances and treaties which drew in many nations.

During the war, the Minister for Magic, Archer Evermonde, passed legislation forbidding the Wizarding community from getting involved. However, many witches and wizards defied that law and helped their Muggle countrymen in the war (Pm). One of those who joined the war effort was Theseus Scamander, older brother of Newt Scamander. Theseus was known as a war hero (WFT). Newt himself claimed to have helped out with dragons on the Eastern Front of the war (WFT).