Brian McKerrow threatened SNP politician Christina McKelvie and repeatedly phoned Panorama journalist Sam Poling.
The 42-year-old, of Larkhall, Lanarkshire, had been on trial at Hamilton Sheriff Court, defending himself.
He was convicted and yesterday a sheriff ordered him to carry out 300 hours' community service.
The court heard Ms McKelvie say he had threatened to "take up arms" against her if she would not take on his case.
The pair first met while she was out campaigning in Hamilton during the 2011 Holyrood elections.
McKerrow had wanted her assistance in getting access to his children but launched into rants against Ms McKelvie and her office staff after he was told she could not help.
The MSP said: "I have never been as unnerved as I have been with Mr McKerrow. At one point he told me that he knew people in the military who would sort us out."
Sheriff Vincent Smith decided not to impose a custodial sentence but gave him unpaid work as a direct alternative to jail.
McKerrow said he planned to appeal the sentence.