Herrera, 25, has joined on a three-year contract after leaving Chilean side Union Espanola, for whom he impressed last season.
The powerful target man scored 11 goals in 21 Apertura matches, adding five in eight in the Copa Libertadores.
Herrera is Montpellier’s fourth acquisition of the summer, following Gaetan Charbonnier, Daniel Congre and Anthony Mounier into the surprise Ligue 1 winners.
He will link up with his new team-mates this weekend for a training session in Mende, with Morocco forward Younes Belhanda also rejoining the squad after international duty.
It is still unclear whether Belhanda, who has been linked with a move to several Premier League clubs, will represent Morocco at the Olympic Games in London.