“I’m also proud of the player trading model we have built, which has brought significant success in recent years.
“But I recognise that both the club and I will benefit from a fresh approach. When I spoke with Dave Cormack and Alan Burrows in the summer, we agreed this was the right time.
“At the same time, I was happy to stay on to lead the club through the summer transfer window and help ensure a smooth transition before a successor is appointed.”
Aberdeen, who currently sit bottom of the Scottish Premiership with no points and without having scored a league goal, say the process to appoint his successor has already started.
In the interim, director David Lawrie will take on the role.
“He has been on an extraordinary journey with the club and can be incredibly proud of everything he has achieved,” said chairman Dave Cormack of Gunn.
“We have shared some wonderful memories together, both on and off the pitch.
“Steven and his family will always be welcome at Pittodrie, and we have no doubt he will go on to enjoy great success in the next stage of his career.”
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