David Dalziel, 62, ex-head of Grampian Fire and Rescue Service, is suing Scottish Fire and Rescue Service over claims of age discrimination and unfair dismissal.
Mr Dalziel said he missed out on leading the national fire and rescue service when it came into being on April 1, despite being recommended for the top job.
The firefighter, who has 44 years' experience, claims the successful candidate, Alasdair Hay, said he wanted Mr Dalziel to be his deputy. But he was unsuccessful at interview and ended up in what he called a "downward spiral" .
Yesterday at an employment tribunal in Aberdeen, Mr Dalziel broke down when he discussed a conversation he had had with Mr Hay on April 1. Mr Dalziel said: "During the conversation Mr Hay said, 'How you leave the service is in your control.' My interpretation - just go."
Mr Dalziel's legal representative Frank Lefevre asked his client how much distress this caused him.
Mr Dalziel said: "Other than I was, in the main, under medical care. It continues."
Despite being recommended for the post by Minister for Community Safety Roseanna Cunningham, he lost out to the former Tayside chief Mr Hay, 50.
Mr Hay is expected to say at hearing this week he clearly warned Mr Dalziel that the deputy's job had to be a fair process.
The tribunal continues.