"But some friends at the time weren't supportive, and thought I was silly to put heart and soul in to it."
Now the face of Adidas Warp Knit Collection, Clinique skincare and Bondi Sands tanning range, Smith puts part of her career success down to a healthy social media following.
But even as the face of some of the biggest brands in the world, the stunning 23-year-old hasn't dodged the haters.
Talking about career opportunities in the US, Smith recalled a casting agent in New York who decided to take her off their books until she had reached she was a smaller size.
"Some people have in their heads a typical look," she said. "In New York, the agency I was working with at the time basically showed me what I looked like, and what I needed to be.
"They said I needed to be all these different numbers.
"I didn't think anything of it at the time, but then they took me off their website and didn't send me to castings.
"I had to go in once or twice a week to be measured, and they told me that until I fit certain measurements they wouldn't show that they represented me.
"It was a slap in the face."
Smith said the experience left her "shocked" because that year abroad was supposed to expand her knowledge of the industry, and working with an international agent.
"It was really hard because I didn't have issues here [in Australia], so I was shocked," she said.
"I became very, very strict on what I was eating. I wouldn't eat out because I was too scared, and I would exercise non-stop.
"Even when I lost the weight, and thought 'OMG I've got to what they wanted', they measured me again and told me to keep going [with the weight loss]."
Smith, who bought her first home in Melbourne earlier this year with her long-term partner Josh, said the experience left a lasting impact on her as a young model.
"I wasn't eating out and it still wasn't good enough," Smith said. "It impacted me a lot. I looked at other girls and got worried.
"Basically, I was keen to get home."
Smith said as soon as she arrived back in Australia, she landed a job with lingerie brand Bras N Things - where they fed her chocolate on set and dispelled any fear of not being good enough.
"I know it's very common for this to happen in the industry," she said.
"But I have friends who have battled seriously [with body image] and haven't been in the industry.
"My diet is very balanced, and as much as I love to eat clean - I do treat myself a lot. Because anytime in the past I've been too strict, I've just gone backwards."
"When people [on social media] say I'm not thin enough, when I first started that was scary, but I have grown to accept that I'm fine.
"I know I am fit and healthy, so I do what I can and I am what I am."
