Rumours have been rife for months that McDaid would be making the switch from The Oval to Windsor Park at the end of his current contract with the Glens.
McDermott confirmed the news the striker would be making the move across Belfast as he announced McDaid is one of three players departing the East Belfast club with a move to David Healy's side seemingly set to be confirmed at the end of the month.
"Robbie scored some vital goals for Glentoran in his five seasons here, most notably, he played an integral role in the Irish Cup success in 2020 scoring the winner in extra-time," McDermott said in a statement on Glens website.
"He successfully took the step with us in 2019 when moving from part-time to full-time football and he played his part in our journey.
"He has surely left some great memories in the hearts of our fans.
"Robbie has decided to move on at the expiry of his current contract and has informed us that he has agreed terms with Linfield FC. We wish Robbie the best in his future.”
Also departing the club following the end of their current deals are Gael Bigirimana and Dillon Powers.
“Bigi has been a top professional during his time at Glentoran," added McDermott.
"His personality is infectious, and I can say that he had a positive impact within our squad.
"Bigi now is considering options as far as Asia, Middle East and Africa. We wish him every success in his next step.
"Having joined us late in the 21/22 season, Dillon showed his quality in the final months of the season.
"We know that with a pre-season under his belt there would be a lot more to come from him.
"However he has decided to return to the US with his family to move into the next phase of his career. He is a top professional and person."