But he argued he had left the organisation and national team in a positive position after decided to quit after almost three years in the post.
Smith, 55, has released a statement through the SFA confirming that the poor health of his parents had been a factor in his resignation. But he made it known that personal concerns had not been the only consideration and that he had been mulling over his future for some time.
"The majority of people I have encountered during nearly three years in the job have been extremely warm, friendly and hospitable towards me," he said. "Inevitably, there has also been a minority who have been less than supportive.
"This has been a difficult enough time, dealing with my mother being admitted to hospital after a fall. To compound matters, she is the carer for my father, who is seriously ill.
"It is not purely personal reasons, or the element of negativity I have experienced, that has made me leave the job. It is a combination of factors. Ultimately, I feel the timing is right."
Smith's decision came amid pressure from Livingston over his involvement in a disciplinary case against Robbie Winters, who was cleared of diving by the SFA's disciplinary committee.
It also came a week before former First Minister Henry McLeish is expected to publish his root-and-branch review of the Scottish game.
But Smith feels the appointment of Craig Levein as Scotland manager is just one reason that Scottish football can move forward with optimism.
"I am certain that Henry McLeish, in his Review of Scottish Football, will outline some significant recommendations and it is my wish that everybody works together to help take the game – both at club and international level – back to its rightful place. We have a top coach in place and a great staff throughout the organisation.
"We have a new, unprecedented broadcasting deal in place (60m], a new kit deal and a renewed optimism for the Euro 2012 qualification campaign.
"We are a profitable business and will continue to be so."