But an hour before the conference, Parky phoned up the club and said he had decided to stay with The Addicks and manager Alan Pardew.
A statement released by vice chairman Andrew Watson read: "Clearly this is a frustrating development for the club, supporters and other applicants.
"Phil applied, attended two interviews - both of which we understand Charlton were fully aware of - and last Sunday he was offered terms. He shook hands with the board of directors and agreed to accept subject to a conversation with his wife.
"On Monday Phil called to accept the position and told Charlton, where he is assistant to manager Alan Pardew. We had agreed he would continue in that role until the end of the season or until Charlton's Premiership status was secured.
"On Tuesday he called to reiterate and asked the club to tie up when the announcement would be made with Charlton chief executive Peter Varney.
"Peter Varney called before lunch yesterday and both parties agreed to announce the appointment at 09.30 this morning.
"Phil then called last night to say that Charlton had made him an unbelievable offer to stay at The Valley and he needed until this morning to decide.
"Clearly this is frustrating news for everyone with the interests of Huddersfield Town at heart."
A statement from Parky read: "I have had a change of heart. I have been enormously impressed with Huddersfield and the integrity of the board. It is a fantastic club with a great infrastructure which will go from strength to strength.
"However, the lure of working with Alan Pardew and in the Premiership was not something I could walk away from."