The promising duo, who linked with Sydney's youth set up in 2017, scored one year deals ahead of 2018/19 campaign.

Midfielder Devlin, 20, arrives from the U20s and first grade NPL, while left back King, 17, has progressed from the U18s squad.

The defender said he was excited at the prospect of working alongside Sydney FC’s record-breaking stars.

“It’s been a dream of mine since I joined Sydney FC’s Academy to one day be part of the A-League squad and I’m so glad it’s come true,” King said.

“All the work I’ve done since I joined the U18’s has prepared me for this step up and I’m looking forward to working under head coach Steve Corica.

“I’m really focused on developing myself as a player and I believe Sydney FC is the perfect place for me to do this. I can’t wait to get started.”

Meanwhile, exciting midfielders Ryan Teague, 16, and Jerry Skotadis, 18 - along with playmaker Marco Tilio, 17 - have signed the club's first A-League scholarships. The trio will be part of the Youth League squad and train with the first team.

Corica said all five players were capable of making the step up.

“We’ve got a fantastic youth system in place and the best Academy in the country,” he said.

“These five players all have a lot of experience at youth level and have shown the qualities necessary to be a part of our A-League squad.

“It’s a tribute to the hard work from everyone in our youth set up that we have been able to offer our first three scholarship contracts and I’m delighted to see them continue their journey with the Sydney FC family.”

The promotions follow a strong season by the club's academy sides.

The U18’s complete ad NSW National Premier League 1 (NPL) Premiership and Championship double on Sunday while the Sky Blues U20’s were narrowly defeated on penalties in their Grand Final after finishing second on the ladder.