Dempster has been recruited after her success at Motherwell and will take up her new post in June.
That will necessitate that Rod Petrie steps down from the position as interim chief executive and will instead act simply as non-executive chairman at Hibs.
The appointment of Dempster - who has worked at Motherwell for over five years - has been met with the universal approval of supporters, according to Riley. Yet he remains hopeful that there will be more wide-ranging changes to the Easter Road hierarchy this summer, including the arrival of a director of football.
"I am quietly confident that it will be a very good move and hopefully it will be a new lease of life and a breath of fresh air for this club," he said. "I made enquiries about her after the news came out and everyone I have spoken to speaks very highly about her and the job she has done at Fir Park. You have to wonder why she would leave Motherwell at this stage.
"She has overseen a tight ship there, helped to pick good players and good managers. So it all augers well. Rod [Petrie] has acknowledged with the appointment of Leeann that he is not happy with the way things have been going. This is his first move to correct that and it could be the first of many.
"There have been whispers of a director of football, also, which I have been saying for over a year that we should really consider. You certainly hope there will be changes - all of these [former Hibs] managers can't be wrong."
Hibs remain gripped by a malaise, of course, and are not yet free from the threat of relegation this season. That has led some supporters to turn their backs on the team but Riley has insisted that those fans will return should the club's fortunes improve.
"It is simple enough: if you put the product on the park then supporters will come back," he added. "If we are playing some attractive football and showing a sense of direction then the crowds will come back. That is what supporters want to see."