A Sydney court on Friday ruled Burgess had intimidated Mitchell Hooke, his ex-wife's father, with the intention of causing physical or mental harm.
Burgess pleaded not guilty to the charge last year, relating to an incident at Mr Hooke's home in 2019.
He was given a conviction and placed on a two-year good behaviour bond.
The court heard competing accounts over the incident, which came as Burgess visited his children after separating from his ex-wife, Phoebe Burgess.
A row escalated after Mr Hooke asked Burgess to leave, the trial was told.
Mr Hooke said Burgess had said: "I'm going to get you. You've set all of this up."
Mr Hooke testified he had felt "absolute terror" that his former son-in-law would hit him during the argument.
Burgess told the court that Mr Hooke had threatened him by saying: "I'm going to destroy you and your career."
Magistrate Robert Rabbidge found in favour of Mr Hooke, ruling that he was an "impressive, believable and consistent" witness.
Mr Hooke is a high-profile political lobbyist in Australia who was previously head of the Minerals Council of Australia.
Burgess, one of Rugby League's biggest stars, was forced to retire in 2019 due to injury.
He was forced to step down from his assistant coach position at the South Sydney Rabbitohs club last October, after police began investigating other allegations against him.
The Australian newspaper reported that the National Rugby League (NRL) club had covered up alleged drug use and domestic violence by Burgess. Burgess has strongly denied the allegations.
The former Bradford Bulls player first joined the Rabbitohs in 2010, rising to become their star player and captain over 182 NRL appearances for the club.
He played 24 matches for England and two for Great Britain.
Burgess also had a short spell in Rugby Union and won five England caps.