The 30-year-old will join the Stags on a free transfer after League One club Southend decided not to offer him a new contract for the 2016-17 season.
"I'm just looking forward to getting my fitness levels to where they need to be so I can be ready to provide for the team," he told the club website.
Hurst made 151 appearances in four years with Southend, scoring 19 goals.
Mansfield will complete the deal on 1 July, but the length of his contract has not been disclosed.
Mansfield have further strengthened their squad for the new season by signing midfielder Kevan Hurst.