Kezia Dugdale’s deputy found out about her resignation just minutes before it was announced, he has claimed.
Alex Rowley, who is now in charge of Scottish Labour, was kept in the dark longer than several media outlets.
In a BBC interview, the Fife MSP was asked if he tried to talk Ms Dugdale out of quitting.
He replied: “No, I didn’t know that Kezia Dugdale was going to resign up until perhaps 10, 15 minutes before she announced it. So no, I didn’t.”
Pressed on the issue, he said he thought very few people knew, adding: “That was Kezia’s decision, it was a decision that she wanted to make.
“We now need to move forward. We owe Kez a debt of gratitude for all the work that she’s done over these last two years but we want to move forward.”
Mr Rowley also refused to be drawn on whether he deliberately set up Nicola Sturgeon to launch an attack on Anas Sarwar, the centrist vying to be Scottish Labour leader.
At FMQs on Thursday, Mr Rowley accused the SNP of “siding with millionaires”, which prompted Ms Sturgeon to lay into Mr Sarwar.
The former dentist responded to pressure over the pay arrangements at his family’s firm by relinquishing his £4.8m stake in the company.
In a speech to delegates on Monday, Mr Rowley is expected to warn that the SNP’s plan to abolish air passenger duty will trigger a “race to the bottom” across the UK.
