Mika Brzezinski, a news reader on the channel's 6am Morning Joe show, repeatedly declined her producer's prompts to broadcast the item, which was top of the running order - and instead made a public show of burning, ripping then shredding her script before moving on to a story about America's Iraq strategy.
An excerpt of the episode has been viewed around three million times on YouTube, giving Brzezinski, who has worked in TV news for 17 years, far more attention than she normally commands in MSNBC's early-morning slot.
"Among journalists it touched a nerve because I think we’re tired of pretending this is important," she told Associated Press.
"We also know that, deep down inside, our viewers know that we don’t believe this is news. They can’t. They can't think we’re that dumb."
In a follow-up segment aired by MSNBC itself, Brzezinski told viewers she had received emails of support from around the world, including messages from former colleagues backing her efforts to change news values.
Many YouTube commenters have praised the anchor for refusing to tolerate celebrity news high in the editorial agenda.
"The journalistic community has heard your statement and it thanks you," her co-host said.