All the former Canberra Demon had heard for two weeks leading into the draft from AFL clubs was radio silence.

So when his phone still refused to ring on Wednesday, the 22-year-old defender thought "bugger it" and headed off to training with South Adelaide.

It was only when he arrived home and saw his face smiling back at him from the television, Highmore knew his AFL dream had come true with St Kilda at pick No.54.

"It was a thrill. Pick 44 was another guy from South Adelaide called Beau McCreery, so I was halfway through messaging him when I popped onto the screen, which was a surreal feeling," Highmore said.

"I was just lost for words to be honest. My best mate flew across from Canberra during the day to surprise me which was cool. We watched it with my two other really good mates here, who I'm living with over here, and weren't expecting too much.

"When my name came up they just erupted and I just sat still for a minute.

"It was an unbelievable feeling, I know it's cliche but it's a dream come true in that moment. Words cant describe the feeling, it's amazing."

Highmore was the Saints' second selection of the night after the club used pick No.26 on Matthew Allison.

It sees the Marist College product link up with fellow Canberran Jack Steele, who was named an All Australian, finished third in the Brownlow and took out the Saints' best-and-fairest this year.

The pair both attended the GWS Giants Academy and trained together for a couple of years, with Highmore excited to have a familiar face at Moorabbin Oval.

"He was one of the first people to give me a call and congratulate me, welcome me, and tell me how good a footy club it is too. That's pretty special there," Highmore said.

"And just to have a familiar face too. Even though he's the star of the AFL, he's always humble and willing to give time to people like me. That's something I'll take on board for sure."

Highmore was brought in by the Saints following a strong campaign for South Adelaide in this year's SANAFL competition.

He overcame an ankle injury in round seven to help the Panthers charge towards the preliminary final, where they fell to eventual champions Woodville-West Torrens.

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"I was able to put my best foot forward, the coach Jarrad Wright put full faith in me," he said.

"The club welcomed with me open arms and have a ripping bunch of guys down there. I was able to get the best out of myself and play pretty consistent footy for the first half of the year before I hurt myself.

"Unfortunately, I completely tore some ligaments in my ankle about round seven, at that point I was playing really good and consistent footy. I couldn't do a whole lot wrong.

"That was a shame and it was tough come back to, because you're unfit and a bit down on confidence. I didn't quite finish the year as I'd like, which probably adds an extra element to why I'm so grateful for the Saints being able to give me an opportunity so I can repay the faith now."

Highmore previously played 48 games for the Canberra Demons, having joined the NEAFL club as a foundation player in 2016.

The mature-age draftee credits Cam Bernasconi, who is now the head coach of Giants Academy, for helping him rise through the ranks to where he is today.

"He's played a pivotal role in my development. That's just something I think he's done a terrific job for the region, with Jack Steele and Tom Green as well," Highmore said.

"He's been critical in that for young players in Canberra and developing talent.

"Just a thanks with mum and dad as well. The Canberra Demons pathway was super for me and South Adelaide worked wonders."