Martin Blunden was the subject of a probe by the service after being suspended in March after complaints emerged which sparked a a bullying investigation six months ago.
It has since been confirmed that Blunded, who was named chief officer in 2019, has now stepped down from the SFRS board.
Scottish Fire and Rescue Service chairwoman, Dr Kirsty Darwent said: “I can confirm that Martin Blunden has stepped down as chief officer of the SFRS.
"As has been previously reported, Mr Blunden was subject to a formal investigation into conduct allegations. Due to confidentiality, I am unable to comment any further.
“We expect the highest standards of our staff and take any allegation regarding their conduct extremely seriously.
“We have robust procedures in place to ensure complaints are investigated in line with our clear policies and procedures.”
Ross Haggart will continue as interim chief officer.