Conversation so far:
What did Stephen Hillenburg start his career in?
Stephen Hillenburg held various jobs in 1984, including as a park service attendant in Utah and an art director in San Francisco, before landing the job he wanted: teaching children.
What subject did Stephen Hillenburg teach when he became a teacher?
Stephen Hillenburg was a marine-biology teacher at the Orange County Marine Institute (now known as the Ocean Institute) for three years.
Did Stephen Hillenburg teach any other subjucts besides marine-biology along the years?
Stephen Hillenburg was a staff artist. During this period, Hillenburg realized he was more interested in art than his chosen profession.
Between the years of teaching marine-biology, did Stephen Hillenburg come up with Spongebob?
He created a comic The Intertidal Zone, to teach his students. It featured anthropomorphic forms of sea life, many of which would evolve into SpongeBob SquarePants characters Bob the Sponge.

Question: What year was he teaching or start?
Self-contained rewrite: What year was Stepen Hillenburg teaching or start?