A Video History of Autism: Leo Kanner
Although he was not the first person to use the word "autistic" to describe autistic people, Leo Kanner is the person who made autism a recognized diagnosis. In 1943, he published a paper called "Autistic Disturbances of Affective Contact," which began the process of defining autism.
In 2010, Caren Zucker and John Donvan found Donald Triplett, one of the subjects of that paper and the first person ever diagnosed with autism. He turned out fine.
Kanner continued to be one of the most influential figures in autism and the field of child psychiatry through the 1970s. He died in 1981.