MSNBC employees are forming a union.

Employees at MSNBC, the 24-hour cable news channel with a slate of prominent liberal anchors, said on Thursday that they planned to form a union representing about 315 workers including producers, bookers, writers and fact checkers.

The announcement is the latest example of a workers’ rights movement that has swept major media organizations, as print, digital and broadcast journalists seek to unionize amid a precarious outlook for their industry. Recently, employees at The Atlantic, The Daily News of New York and Insider, as well as tech workers at The New York Times, have announced their intent to unionize.

The MSNBC bargaining unit would be represented by the Writers Guild of America, East, which said a clear majority of the network’s employees had signed a letter seeking voluntary recognition of a union. The Writers Guild represents many news and entertainment outlets, including ABC News and CBS News, whose involvement dates to the guild’s beginnings in 1954.

Two star MSNBC hosts, Chris Hayes and Joy Reid, immediately expressed support for the unionization effort. “Extremely proud of my colleagues,” Mr. Hayes wrote on Twitter, adding an emoji of a fist in solidarity.

Management at MSNBC was informed of its employees’ effort on Thursday afternoon. “We’re looking forward to continuing the type of direct, open and honest communication that has already resulted in meaningful change at the network,” Rashida Jones, the network’s president, said in a statement.

In a follow-up memo to staff, Ms. Jones said the network would request a formal vote on unionization by employees, rather than voluntarily recognize the new union. “I respect our employees’ right to decide whether they want to be represented by a union, and I believe our employees should be able to make such an important decision through a standard election process,” she wrote. “It is important to give everyone who would be included the chance to understand what this would mean before making their choice.”

The Writers Guild objected to requiring a formal vote. “MSNBC needs to follow its own progressive principles and honor the decision made by its editorial employees to unionize,” the executive director of the guild, Lowell Peterson, said in a statement late Thursday.

Digital journalists at NBC News, a corporate sibling of MSNBC, unionized in 2019 with the NewsGuild of New York, which also represents journalists at The Times. They have not yet settled on a contract with NBC.

“We as journalists believe that democracy works, as a nation, state, country, city or in a workplace; things work better when policies are made with input from the people,” said Andrew Joyce, a segment producer at “The Rachel Maddow Show” who helped lead the MSNBC organizing effort.

The prospective new union would also include workers at “The Choice,” a digital news and commentary service available on NBC’s streaming network, Peacock.

In a message on Thursday, the MSNBC bargaining unit wrote, “We are standing up for each other and our work — because this is who we are.” It was a play on a marketing campaign by NBC News and MSNBC featuring anchors and correspondents explaining their commitment to the news with the slogan “This is who we are.”

Ms. Jones, who started as the network’s president this year, is the first Black woman to run one of the three major cable news networks. Stephanie Brumsey, a segment producer of the weekend show “The Cross Connection,” said before Ms. Jones’s follow-up memo that she was “very hopeful” that the new leadership would voluntarily recognize the union. “It’s not the old guard that’s there,” she said.