Labour's head of strategy is to formally step down from his role this week, he has announced.
Rami Okasha's departure comes a month after former general secretary Colin Smyth said he was resigning, in a move seen as giving Scottish leader Johann Lamont more authority after a shake-up of party structure.
Labour had previously said Mr Okasha was on leave and refused to comment on media reports he had been suspended.
Mr Okasha said: "Being at the heart of a political party is a real privilege and I have worked alongside tremendously talented people.
"I have been part of a team running the last European, general and Scottish elections, winning three parliamentary by-elections, and this year's local authority campaign, so now is a good time to move on to new challenges.
"I strongly support Johann in her efforts to build a new Scottish Labour Party and look forward to playing any role I am asked."
He worked for the party for four-and-a-half years, leading communications in seven major campaigns.
Ms Lamont said: "I would like to thank Rami for his dedication and service to the Scottish Labour Party. He is a man of considerable merit and no one could ever say he didn't put in the hours. He leaves with my best wishes and I hope he enjoys the success he deserves in his future career."
Iain McNicol, Labour's general secretary, said: "Rami Okasha has been and remains a dedicated servant of the Labour Party, as a member, activist and superb employee.
"I wish him all the best for the future. He leaves his post with many friends in the party."
