The company said the Benioffs' acquisition of the magazine would be a personal purchase and would not be connected to Salesforce.com, where Marc Benioff is the founder and co-chief executive.
The transaction is subject to customary closing conditions and regulatory approval and is expected to close within 30 days.
The family does not plan to have any role in day-to-day operations and said they are not looking to buy other magazines.
The Benioffs' purchase of Time will be kept separate from Salesforce, and the couple plans to take a hands-off approach to managing the magazine.
Meredith said Time reaches a combined audience of more than 100 million readers in print and online, with more than 50 million digital visitors and 40 million social followers each month.
South Korea launches its first missile-capable submarine
And it said North Korea is violating sanctions by transferring coal at sea and flouting an arms embargo and financial sanctions. The Korean War ended in 1953 with an armistice, not a peace treaty, and both sides remain technically at war.
It's not the first foray into media for a head of a tech giant, with Amazon's Jeff Bezos in 2013 purchasing the Washington Post for $250 million.
Through the deal with Benioff, Meredith will still provide "services such as consumer marketing, subscription fulfillment, paper purchasing and printing", according to the company. Those decisions will continue to be made by Time's current executive leadership team, the announcement said.
"We are honoured to be the caretakers of one of the world's most important media companies and iconic brands", the Benioffs said in a statement on Sunday (Sept 16). "Meredith will also be able to include the Time brand in large corporate advertising buys".
The development was announced to Time staffers by its editor in chief Edward Felsenthal, who told employees on Sunday night that "Benioffs will hold Time as a family investment".