Soon after they moved to the US and Robson became a regular visitor to the self-described King of Pop's Neverland Ranch in California and on Jackson's concert tours, but behind closed doors he said he was abused.
"He performed sexual acts on me and forced me to perform sexual acts on him," Robson said.
Robson has repeatedly denied under oath that Jackson abused him, including at Jackson's 2005 child molestation trial where he was acquitted.
Robson was the first witness called by Jackson's defence team.
The Australian rejected media reports that he had suffered repressed memory, but said it was only last year, during his second nervous breakdown and while he was looking at his own 18-month-old son imagining how he would feel if he was a sexual victim, that he began to understand what Jackson did to him.
"I never forgot one moment of what Michael did to me, but I was psychologically and emotionally completely unable and unwilling to understand it was sexual abuse," he said.
"My son is the one who saved my life."
Robson said when he was 11 and Jackson was being investigated for molestation in 1993, the singer would call him every day to "role play" what he should say if questioned.
"It was complete manipulation and brainwashing," he said.
The same happened before the 2005 molestation trial.
"He would also tell me then if anyone thought that we did these things, any of these sexual things, both of us would go to jail for the rest of our lives," Robson said.
Robson has filed a claim in a Los Angeles court against the dead singer's estate.
When interviewer Matt Lauer asked Robson why he didn't approach Jackson's estate quietly with the complaint, he said he had been silent long enough.
"I have lived in silence and denial for 22 years and I can't spend another moment in that," he said.
Robson said he believed there were other victims.
"There is no excuse for what he did to me, and I believe many others, but he was a troubled man," Robson said.
A lawyer for Jackson's estate, Howard Weitzman, labelled Robson's delayed allegations as "outrageous and pathetic".
"This is a young man who has testified at least twice under oath over the past 20 years and said in numerous interviews that Michael Jackson never did anything inappropriate to him or with him," Mr Weitzman said.
"Now, nearly four years after Michael has passed, this sad and less than credible claim has been made."
- AAP
