By the time of the first wizard war when Voldemort was rising for the first time.
Moody was now a well known auror and member of the Order Of The Phoenix.

He is well known for filling half the cells in Azkaban.
In doing this he made lots of enemies from mostly families of the people he arrested.
He became paranoid and once destroyed a present thinking it was a hidden basilisk egg.

Fighting the dark lord came with a price he lost his leg his eye and his nose which he all lost before the end of the war so when Voldemort got defeated he retired from being an auror.
But he wanted to pass his skill and knowledge onto someone worthy so he chose Nyphadora Tonks.

Shortly before he retired he caught the death eater Igor Karkaroff who he greatly disliked.