Neil Campbell, 69, was found guilty of seven sex abuse charges against members of the same family at Portree Sheriff Court yesterday.
Jurors appeared shocked as details of a previous conviction for a 2007 attack on a woman doctor were read out. He also has a number of other sex convictions.
Campbell had pleaded not guilty to offences carried out at his farm at Talisker, near Carbost, and in nearby lay-bys between 1995 and 2011.
He had lodged a defence of criminal insanity after claiming a serious brain injury suffered in a road accident more than 30 years ago caused him to commit indecent exposure.
The jury chose to believe the evidence of one expert who said Campbell was not insane and was "responsible for his own actions."
A father of some of the victims said Campbell had apologised to him repeatedly after he confronted the farmer about an inappropriate approach to his 15-year- old son.
His other abuse victims described him as "vulgar, perverse and disgusting" and one boy, now 29 said he feared what Campbell might do to him if he hadn't got out of his Land Rover in the lay by.
Campbell also faced accusations in court of attempting to bribe a victim into not reporting attacks.
Sheriff Jamie Gilchrist deferred sentence until next month for background reports and a risk assessment. The abuser's wife was in court.