Former Australian Tax Office deputy commissioner Michael Cranston says he was "just doing my job" after he was exonerated of misusing his senior position in the public service to pass information on to his entrepreneur son.

After nearly three weeks on trial before NSW District Court judge Robyn Tupman, a jury took two days to find the 40-year ATO veteran not guilty of dishonestly obtaining information in his capacity as a senior public servant to benefit Adam Cranston, as well as a charge of using his influence to improperly obtain a benefit for his son.

Mr Cranston said outside court that he was "absolutely shocked" when he was charged.

"I just know looking at what I did, I was just doing my job, passing on a matter. I declared my conflict about my son and that’s what I do everyday," he said.