Leadership of the combined Associations, the Screen Actors Guild and American Federation of Television and Radio Artists (SAG-AFTRA), have accused the former US president of inciting the deadly attack on Congress on January 6.
They also accused Mr Trump of sustaining a reckless campaign of misinformation aimed at discrediting and ultimately threatening the safety of journalists.
SAG-AFTRA have in membership about 160,000 actors, journalists and other media professionals in the US.
SAG-AFTRA President Gabrielle Carteris said: “Donald Trump attacked the values that this union holds most sacred – democracy, truth, respect for our fellow Americans of all races and faiths, and the sanctity of the free press.
“There’s a straight line from his wanton disregard for the truth to the attacks on journalists perpetrated by his followers.”.
Mr Trump, who has been a Guild member for more than 30 years and appearing in a number of films, including Home Alone 2 and Zoolander plus the US version of The Apprentice TV show, was considered for expulsion at a meeting on 19th January with the setting up of disciplinary committee to investigate his matter.
The disciplinary committee was about to reach a conclusion, before Mr Trump wrote to the guild’s president Gabrille Carters on Thursday, about quitting.
He wrote: “While I’m not familiar with your work, I’m very proud of my work on movies such as Home Alone 2, Zoolander and Wall Street: Money Never Sleeps; and television shows including The Fresh Prince of Bel-Air, Saturday Night Live, and of course, one of the most successful shows in television history, The Apprentice – to name just a few!
“I’ve also greatly helped the cable news television business (said to be a dying platform with not much time left until I got involved in politics), and created thousands of jobs at networks such as MSDNC and Fake News CNN, among many others.
“Which brings me to your blatant attempt at free media attention to distract from your dismal record as a union.”
SAG-AFTRA said they represent thousands of broadcast journalists across the US, and there are reports of intimidation and physical assaults on media and journalists, which escalated throughout Mr Trump’s presidency.
Mr Trump continued in his letter: “Your organization has done little for its members, and nothing for me – besides collecting dues and promoting dangerous un-American policies and ideas – as evident by your massive unemployment rates and lawsuits from celebrated actors, who even recorded a video asking, ‘Why isn’t the union fighting for me?
“These, however, are policy failures. Your disciplinary failures are even more egregious.
“I no longer wish to be associated with your union.
“As such, this letter is to inform you of my immediate resignation from SAG-AFTRA. You have done nothing for me.”
In response, the union’s president Ms Carteris and national executive director David White said: “Thank you.”