Polo, who was delisted by Richmond at the end of the 2010 season, was a surprise selection by the Saints in last week's NAB AFL Draft.
In fact there were audible gasps in the Gold Coast convention centre when Saints recruiting manager John Peake read the 24-year-old's name with the 103rd selection.
Polo said he feared his career may have been over when the Tigers cut him.
"You always have that in the back of your mind and it's not a very nice feeling, but I felt that I've still got so much to offer in AFL football," he said.
"I've been given that opportunity and now that I have, there is no looking back and I'm going to take a hold of it."
Polo played just four games for Richmond in 2010 but says his ability to be used in multiple roles would hold him in good stead.
"I'm injury-free at the moment," Polo said. "I had a shoulder reco a couple of years ago which made me take a step backwards.
"I think my versatility would be a good thing for the club. I can play in the midfield and down back."
St Kilda coach Ross Lyon said Polo still had a lot to offer at AFL level.
"In his [Polo's] first game he had 30 disposals and kicked three goals," Lyon said. "That doesn't disappear."
Fellow recruit Ryan Gamble said he was hoping to cement a spot in the St Kilda line-up and had already identified a position for himself.
"Obviously you've got the two talls in Nick Riewoldt and Justin Koschitzke and then the small blokes in [Stephen] Milne and [Adam] Schneider," Gamble said.
"They are missing that mid-sized forward. I reckon I could step in there and offer something."
Gamble left Geelong at the end of 2010 after struggling to consolidate a spot in the side.
He spent much of the year toiling away at half-back in Geelong's VFL side but said he was more suited to the other end of the ground.
"Last year the coaches came to me and wanted me to play in the backline. I thought realistically the only place I could get into the Geelong team was the forward line," Gamble said.
Lyon said acquiring Gamble would help the Saints develop defender Sam Gilbert into a forward and that both Gamble and Polo would continue to develop under the Saints' tutelage.
"We believe we have a really strong system here," Lyon said. "We can bring both of the players on."
