Smith bowed out with gold in the 100m breaststroke and silver in the 200m breaststroke, switching her podium positions from Tokyo.
Now, at the still tender age of 27, she is planning a career out of the pool.
Smith told AFP that while she is looking forward to adjusting to a less-regimented life, she is already sketching out a role in athlete representation.
"I'd love to do that. Especially in South Africa, we don't have anyone that really truly represents swimmers, understands how we think as swimmers," she said.
Smith is motivated to help the next generation reach the top, and is acutely aware of the obstacles in their path.
"I think we don't have the financial backing in swimming at all," she said. "So you really have to win to get sponsors. And if you're not, if you don't have gold, then you don't have anything.
"So it is really challenging because it's exactly in that time period of building up to gold that people lose interest or don't have the financial capacity to give themselves to world championships and stuff like that, where they then drop out."
Help others
Smith hopes the networks she has built up during her career can help smooth the path for potential future champions.
"I think that previous athletes or previous Olympians, you get so fed up with the federations and everything that happens that you almost just leave and you're just like, 'I just want to get out of here.'
"I think we all feel like that sometimes. But I think for me personally, I'm just deciding, if someone's not going to change it, who's going to help them?"
While Smith has not definitively made up her mind on her next steps, she says she is glad she came to Paris knowing it would be her last Games.
"It's been so fun," she said. "I think knowing and having peace before just really made enjoy those moments.
"It's like, 'Oh, it's my last warm-up. It's my last cool down.' I think when you know it's your last, then it's so nice to really enjoy that moment.
"I'm definitely going to miss it. I think I second-guessed myself a few times. Even walking out of the final, I was like, "Should I? Should I retire?' But yeah, I'm at so much peace with the decision and I'm excited to see what lies ahead."
Mention of recently retired tennis star Andy Murray being spotted eating a doughnut in Paris brings a smile from Smith, who says she is ready to deal with a less restrictive lifestyle.
"My life has been so planned. And now to not have any plans is almost strange. Sometimes you doubt and you fear a bit towards it," she said.
"But I know that I don't have any control over my future and that I must just trust God that he'll have a plan and trust that I built enough character in me.
"Swimming has taught me enough to be able to deal with the rest."
