Her comments were about U.S. education secretary Arne Duncan. Lewis made them were made during a videotaped speech in Seattle last month. She also made comments about her own drug use.
While the elected union leader apologized Wednesday, she cast herself as a victim of a smear campaign by a school choice group that distributed the video to the media.
"Some of what I said was inappropriate and insensitive. No one should ever resort to personal attacks," Lewis said.
In a 35-minute speech about education to social justice teachers in Seattle last month, Lewis mocked Duncan, saying "Now you know he went to private school because if he had gone to public school he would have had that lisp fixed." Watch the entire video of Lewis' speech
"I spoke to Arne Duncan. He said, look, I understand, don't worry about it. He didn't take it personally," she said Wednesday.
Lewis' comments in the speech about her own drug use in college also drew criticism. "People are impressed. Let me tell you. I spent those years smoking lots of weed, self-medicating," she said.
"It is what happened. I told the truth about my past," said Lewis Wednesday.
She blamed what she called a neo-conservative anti-labor and anti-education blogger for distributing the video to the media. The Education Action Group, based in Michigan, circulated the video after finding it on YouTube.
"She's being held accountable for her own words. She doesn't' like it so she's lashing out at us. She's calling us names now. It is just ridiculous," said Kyle Olson, Education Action Group.
Lewis admits some of her fiery words come out of frustration with Chicago Public School officials and with Mayor Rahm Emanuel
With contract negotiations coming up former union employee Rosita Chatonda believes the video tape will hurt the union.
"All of side things that are going on really impact negatively on the ability to be able to negotiate," said Chatonda.
Lewis said she does not think she will lose support among the rank and file over the controversial comments. When asked if she knew the speech was being videotaped, Lewis answered, "yes, I didn't swear."
While the group that distributed the video to the media admits it does not support teachers unions, the Education Action Group says it searched Karen Lewis on YouTube after she declined an interview for a short documentary.
There was no comment from CPS officials.