Sarah Driscoll was out for drinks with colleagues one evening in early 2017 when a veteran political operative she worked with, Adam C. Sullivan, cornered her at a Washington bar.

They were both directors of the Hub Project, a small Democratic advocacy group leading a pitched fight against Donald J. Trump’s new presidency. But rather than talk politics that night, Mr. Sullivan launched into an uninvited and graphic sexual rant, Ms. Driscoll recalled.

He said “I bet you slept with the whole Democratic Party,” she said, and spoke of his own sexual prowess. He boasted about his penis size and described the ways he would like to sleep with her, as Ms. Driscoll listened, speechless.

“I was kind of in shock,” she recalled in an interview with The New York Times. “I just was very numb and couldn’t believe what had just happened. And once it set in more, I felt really gross.”

Ms. Driscoll did not lodge a formal sexual harassment complaint until mid-July that year, when a woman she supervised came to her recounting a similar experience. A human resources specialist investigated, found the claims credible and in the last days of July, the Hub Project quietly fired Mr. Sullivan.

Less than a year after the incident, which has not been previously reported, Mr. Sullivan landed on his feet — running the re-election campaign of Kathy Hochul, then the lieutenant governor of New York. The two had worked together before: In 2011, he helped Ms. Hochul, a Democrat, win a special election for Congress, and she later recommended him for the job at the Hub Project.

It is not clear what Mr. Sullivan told her about his time at the Hub Project. But the sequence of events places scrutiny on the judgment of Ms. Hochul, who, three years later, after she became governor following her predecessor’s own sexual harassment, vowed to “change a culture of harassment and abuse, and ensure safe, respectful workplaces.”

The women from the Hub Project came forward after The New York Times published an article that documented Mr. Sullivan’s demeaning treatment of staff on Ms. Hochul’s 2022 campaign and cast doubt on his stewardship of her political operation. Ms. Hochul cut ties with him on Sunday, when she said that she was surprised and disappointed to learn of the behavior described by The Times.

The new allegations from the Hub Project appear to be part of a pattern of troubling behavior as Mr. Sullivan, 43, bounced around the country as a campaign manager for prominent Democrats.

Four people who worked with him — going back years before his tenure at the Hub Project, and as recently as her race for governor last year — described incidents to The Times in which he made unwanted sexualized remarks. They recalled situations similar to those Ms. Driscoll detailed, in which Mr. Sullivan made inappropriate comments, often while drinking, about female colleagues’ bodies or romantic lives.

The campaign aides spoke on the condition of anonymity because they continue to operate in Ms. Hochul’s orbit and feared retaliation.

At the Hub Project, Sarah English, the second woman who came forward after Ms. Driscoll, said in an interview that Mr. Sullivan had asked crude, invasive questions about her sex life.

The Times interviewed a third woman at the Hub Project who said Mr. Sullivan also demanded she answer questions about sex as he vividly described his own exploits. But she said she had not reported it at the time or been aware that others had received similar treatment until they began sharing experiences last week.

New Venture Fund, the umbrella group that houses the Hub Project, confirmed the outlines of the women’s account in a statement.

“New Venture Fund’s policy is to expediently, thoroughly and fairly investigate claims of impropriety among its staff,” it wrote. “In strict adherence to the policy, New Venture Fund investigated the allegations immediately, and subsequently terminated the employee.”

In response to a list of detailed questions, Mr. Sullivan emailed a one-line statement: “I apologize to anyone I made uncomfortable at any point,” he wrote.

After he left the Hub Project, Mr. Sullivan had other recent consulting clients, including the Reform Alliance, but Ms. Hochul appears to be the only politician who worked with him. He helped her build her new administration, managed a turbulent campaign for a full term in office, advised her on multibillion-dollar budget priorities and served as her conduit to the state Democratic Party.

He has done all of it, though, with an unusually low public profile: He never took a job in state government, had no formal campaign title and was paid more than $500,000, mostly through a secretive arrangement that kept his name off campaign finance records. He also worked from his home in Colorado.

Asked to comment on Wednesday, Ms. Hochul reiterated that she had not known of the claims against Mr. Sullivan.

“Sexual harassment is unacceptable under any circumstance, and these allegations are both shocking and deeply disappointing,” she said in a statement. “No one should have to tolerate this type of behavior, and I condemn it.”

Mr. Sullivan joined the Hub Project in 2016 as one of the group’s first employees after more than a decade running campaigns for Democrats like Kirsten Gillibrand of New York, Martin Heinrich of New Mexico and Mary Landrieu of Louisiana.

Founded by the Democratic strategist Arkadi Gerney, the group was originally set up to build support for liberal policies in anticipation of a Hillary Clinton presidency. When Mr. Trump won, the 18 or so employees there pivoted to become leading organizers of the resistance to his agenda.

Ms. Driscoll, who had worked on President Barack Obama’s 2012 campaign, began working at the Hub Project as its digital director not long after Mr. Sullivan started.

Ms. Driscoll and others said that Mr. Sullivan created a toxic work environment, belittling and disrespecting women to the point that she actively sought to avoid him until one night in early 2017. Ms. Driscoll, 35, had joined her colleagues at a work-sponsored happy hour at the Blaguard, a bar in Washington’s Adams Morgan neighborhood, where Mr. Sullivan began haranguing her about her sex life and his own.

“I’ve always gotten rave reviews,” Ms. Driscoll recalled him saying that night. “I know how to pleasure a woman.”

Ms. Driscoll was able to pull herself away. She recalled going home to tell her boyfriend, now her husband, about the encounter through tears, and she soon told a friend. But in the days before the #MeToo movement, she worried that Mr. Sullivan, who appeared to get along well with men in the office, would retaliate against her and that he would ultimately face no consequences for his actions.

She said she regretted not reporting the encounter sooner.

“I’ve always had this fear that he was still out there, working in Democratic politics, making a ton of money and, most importantly, continuing to harass women,” Ms. Driscoll said, explaining her decision to publicly describe her own experience. “And it’s always weighed on me.”

Ms. English, a graphic designer who worked under Ms. Driscoll, had her run-in with Mr. Sullivan a few months later. He had invited her and a few colleagues for celebratory drinks at Mission, another bar near the group’s Dupont Circle office, after a successful presentation to funders, she said.

Ms. English found herself alone at the bar with Mr. Sullivan, who had been drinking steadily and began asking her about her sex life. She said he repeatedly called her a “hot girl” and demanded to know how many times a week she had sex with her partner. She demurred, but he persisted, saying she should leave her partner if they were not having weekly intercourse.

“My response was anger that someone in a position of power would speak with me like that, especially knowing that I’m a younger, lower-level employee compared to him, especially working for a progressive nonprofit organization,” Ms. English, 35, said in an interview.

She said she did not report the incident to Ms. Driscoll until several weeks later, when she began to suspect that Mr. Sullivan was retaliating against her in the office.

Andrea Purse, who was the director for communications at the Hub Project, confirmed that Ms. Driscoll had told her at the time that she and a colleague had reported being sexually harassed by Mr. Sullivan.

Ms. Purse recalled that soon after, Mr. Gerney told a small group of senior leaders that Mr. Sullivan had done something inappropriate that he could not discuss in detail and that he would not be returning to his position. Mr. Gerney, 48, declined to comment and referred questions to the New Venture Fund.

A third woman whose work at the Hub Project was overseen by Mr. Sullivan recounted a similar experience during an office happy hour at Mission. She said she ended up alone at the bar with Mr. Sullivan, who began asking invasive questions about her sex life and speculating about the number of sexual partners she had while boasting about the frequency with which he had intercourse.

The woman, who spoke on the condition of anonymity because she was worried about harming her career, said she found a way out of the conversation and tried to forget about the encounter.

Ms. Driscoll and Ms. English said they were not asked to sign nondisclosure agreements at the time and were happy with how the complaints were handled. Management did not share the reason for Mr. Sullivan’s departure broadly.

In an Aug. 1, 2017, email to colleagues saying goodbye, Mr. Sullivan wrote simply that he had left the Hub Project “as you have all heard.”

“I have enjoyed working with all of you,” he wrote in a copy of the email reviewed by The Times. “And wish you all the best in the important work that lays ahead.”