Senator Al Franken of Minnesota apologised on Thursday after being accused of sexually harassing the journalist Leeann Tweeden in 2006, highlighting the comedian-turned-politician’s past history of crass jokes towards women.

During Franken’s time as a comic, which included two long stints on Saturday Night Live from 1975-1980 and 1985-1995, he came under fire for telling sexist jokes, some of which made light of sexual abuse and rape.

In a 1995 New York Magazine profile of Saturday Night Live, Franken is quoted making vulgar jokes about rape during a brainstorm for a sketch written by Norm MacDonald that involved sedatives. “‘I give the pills to Lesley Stahl,’” Franken says, referencing the CBS News reporter while pitching a line for the sketch. “‘Then, when Lesley’s passed out, I take her to the closet and rape her.’ Or, ‘That’s why you never see Lesley until February.’ Or, ‘When she passes out, I put her in various positions and take pictures of her.’”

Al Franken and Leeann Tweeden perform a comic skit in 2006. Photograph: Handout/US army

Franken was also highly criticized during his initial 2008 senatorial campaign for an article he wrote for Playboy Magazine in 2000, in which he imagines a fictional Institute for Pornographic Studies in Northridge, California.

“As Dr. DeVine led me to the Future wing of the institute, I couldn’t help but notice that she is an extremely attractive blonde with a tight, round ass, legs that won’t quit and firm but ample breasts,” Franken wrote. “So ample, in fact, that she received a full scholarship from MIT.

“I found myself extremely attracted to the vulnerable side of this sexy scientist, and when I offered to comfort her, she accepted, kissing me full on the lips and inserting her tongue into my mouth and moving it around suggestively,” the piece continues. “Then she reached down and started rubbing my crotch and within just five or ten minutes, my cock was again hard and ready for action.”

On at least one other occasion, Franken has been quoted making jokes about child rape, including at a Comedy Central roast of director Rob Reiner, and women, including at an event hosted by the Feminist Majority Foundation in 1999, where he said: “Why don’t we focus on what Afghan women can do? They can cook, bear children, and pray. As I recall, that was fine for our grandmothers.”

Franken apologised to Tweeden in a statement made shortly after the news anchor for TalkRadio 790 KABC in Los Angeles wrote about how he had required them to kiss on the lips to prepare for a script and was photographed groping her breasts while she slept.

“I respect women. I don’t respect men who don’t,” Franken wrote. “And the fact that my own actions have given people a good reason to doubt that makes me feel ashamed.”

Tweeden gave a press conference on Thursday responding to Franken’s apology. “The apology, sure, I accept it, yes. People make mistakes and of course he knew he made a mistake. So yes, I do accept that apology,” she said, going on to comment about the a proposed ethics investigation into Franken and calls for him to step down.

“The ethics investigation? If that’s what Mitch McConnell wants to do, that’s on them. I’m not calling for that. I’m not demanding that,” she said. “I’m not calling for him to step down. That’s not my place. That’s not my call. I’m not saying that. People make mistakes.”

In the wake of the allegations, numerous senators have publicly denounced Franken’s behavior, including the Democrats Elizabeth Warren, Kirsten Gillibrand and Dick Durbin. Tweeden’s account of the senator’s misconduct comes as sexual assault allegations send shockwaves through Hollywood and Washington, with producer Harvey Weinstein and Alabama senatorial candidate Roy Moore, among many others, facing accusations by numerous women.