According to a statement released by the ABC, the decision was made when the directors resolved that it was not in the best interests of the ABC for Ms Guthrie to continue to lead the organisation.
He said he could not provide any further insight into why the ABC board removed Ms Guthrie. "I am considering my legal options", she said.
Mr Milne conceded Ms Guthrie had done a "pretty good" job turning the ABC towards its digital future.
In an email sent to ABC staff, Mr Milne said "a change in leadership does not mean a change in strategy".
He said the decision to sack the managing director was not a reflection on the selection process when she was appointed as Mark Scott's successor.
"That's what they're responsible for, and I'll hold them to account for that".
ABC chair Justin Milne said "In resolving to seek fresh leadership, the Board's foremost consideration was the long-term interests of our own people and the millions of Australians who engage with ABC content every week".
A number of high-profile ABC personnel welcomed the news of Ms Guthrie's dismissal, including ABC Melbourne radio host Jon Faine and Four Corners executive producer Sally Neighbour.
Anderson will serve as acting managing director while Guthrie's permanent replacement is found. Anderson is now Director, Entertainment & Specialist and has worked in the media industry for more than 30 years.
The former Google Asia-Pacific, Foxtel, BSkyB and Star TV executive was half way through her five-year term. She has copped criticism for her employment history with News Corp and a perception she did not defend the ABC enough from opponents of the public broadcaster; and also came under fire for repeated controversial on-air episodes which upset members of the conservative Coalition government. He added the directors felt the ABC "would do better under different leadership" but that she had "done a good job".
"At no point have any issues been raised with me about the transformation being undertaken, the "Investing in Audiences" strategy and my effectiveness in delivering against this strategy".
"Michelle challenged us in a lot of ways to be better, challenged us to free up more money for content and went about that over the last two-and-a-half years."