Montagna on Wednesday announced his retirement after 287 games and 16 seasons for the Saints.
The club had already farewelled Riewoldt, with the pair playing almost all of the careers together.
'Joey' Montagna told his teammates on Wednesday afternoon of his decision.
'For the past 16 years, the St Kilda football club has been my home and I couldn't be more grateful for the opportunity to play out my career as a one-club player,' the 33-year-old said.
Montagna said he would leave the game content, knowing he had given everything he could, finishing in the top four of the club's best-and-fairest award nine times in the past 10 seasons.