"I have resigned as an adviser to Harvey Weinstein", Bloom wrote on Twitter on Saturday.
Trump saying he's "not surprised" suggests that like many Hollywood insiders and heavyweights, he knew about Weinstein's behavior and did nothing to stop it.
Weinstein was a major supporter for Hillary Clinton's failed run for the presidency, donating tens of thousands of dollars to her campaign and throwing celebrity fundraisers for the Democratic nominee.
Asked about the tape on Saturday, Trump dismissed it "locker room talk", as he has done in the past.
The statement was signed by four of six remaining board members.
Sivan claims that a decade ago, while working as an anchor for local cable channel Long Island 12, Weinstein sequestered her in the kitchen of a Cuban restaurant in which he was an investor.
Bloom's planned strategy, as written in her email, included "photos of several of the accusers in very friendly poses with Harvey after his alleged misconduct", according to the Times.
During an appearance Friday morning on Good Morning America, Bloom, who had been advising Weinstein on gender and power dynamics, said he had behaved inappropriately and agreed with an interviewer who characterized his reported actions as illegal.
Trump's comments were also made one day after Weinstein took an indefinite leave of absence as the co-chairman of The Weinstein Company, the hit-producing Hollywood studio.
After the Times published its first report on the allegations against Weinstein, Bloom issued a statement Thursday saying that although Weinstein "denies numerous accusations as patently false", he would not "demean or attack" his accusers. She added that she was happy women have come forward with their allegations.
Sivan claims she has had no further contact with Weinstein since the incident.
This comes after widespread criticism of Bloom on social media and by her own mother, who said in a statement, "Had I been asked by Mr. Weinstein to represent him, I would have declined, because I do not represent individuals accused of sex harassment".
In the days since the Weinstein scandal broke, the 65-year-old producer has sent a series of mixed messages in response to the lurid allegations.
The New York Times has stated that it stands behind its story.