Mr Mitchell, 59, gave evidence in Brisbane District Court on Tuesday for the second day of his defamation trial against YouTube creator Karl Jobst.
Mr Mitchell rose to fame in the 1980s and '90s through recognition of his high scores in the arcade games Donkey Kong and Pac-Man.
The Florida resident claimed his reputation was damaged and he lost out on $US65,000 in paid work as a result of a video Mr Jobst posted on May 26, 2021.
On Monday Mr Mitchell gave evidence that he was physically sick when viewing Mr Jobst's video, which he said implied he "hounded a young man to commit suicide" by suing Ben Smith, another YouTuber.
Under cross-examination on Tuesday, Mr Mitchell was asked about text messages he sent about Mr Smith, known online as Apollo Legend, in response to social media rumours about his death.
"My wife found two different places online (that) Apollo Legend is dead. If it's true I will not shed a tear. I will try not to smile or giggle. No promises," Mr Mitchell said in a text message.
The message was sent three years before Mr Smith took his own life in December 2020, several months after settling a defamation lawsuit over claims Mr Mitchell had cheated to obtain high scores.
Mr Jobst's barrister Michael de Waard asked Mr Mitchell if the text messages undermined his claim to have been saddened by the news of Mr Smith's death and made ill by being accused of contributing to it.
Mr Mitchell said his messages were "dark humour" made when he did not believe Mr Smith had died as the news came from anonymous social media users.
"I regret doing it. I wish I didn't do it as three years later ... it came true," he said.
Brisbane YouTube video creator Karl Jobst is being sued for defamation. (Darren England/AAP PHOTOS)
Mr Mitchell has testified he returned to the public eye after 2007 largely due to his role in the documentary film King of Kong.
Multiple internet forum users and YouTube creators would later allege Mr Mitchell had cheated in high score competitions by not playing on original arcade machines.
Mr Mitchell said on Tuesday he had sued people and video game high score adjudicators for defamation over claiming he "lied and cheated to get my scores".
He denied he had a pre-existing negative reputation and people expected him to sue those who claimed he cheated.
Mr Mitchell at times appeared angry while on the stand and said he was expected to "just answer a question and shut up" when he wanted to say more.
Mr de Waard asked Mr Mitchell if his own YouTube channel contained the only video remaining online accusing him of causing Mr Smith's death.
Mr Mitchell said Mr Jobst's original video was seen by more than 500,000 people and the version with the claims edited out continued to prompt discussion about Mr Smith's death.
The trial continues before Judge Ken Barlow.
Lifeline 13 11 14
beyondblue 1300 22 4636
