Carlisle, who played for Burnley and QPR, tried to take his own life in December when he was hit by a lorry.
"People are delicate stepping around it - there's no shame invested in it for me," the 35-year-old said. "I attempted suicide because I was very unwell."
Carlisle was at the launch of a charter committed to tackling the stigma surrounding mental illness.
The Football Association, Rugby Football Union, Lawn Tennis Association and the England and Wales Cricket Board are among the sport governing bodies to have signed up to the Mental Health Charter for Sport and Recreation.
Carlisle suffered cuts, bruises, internal bleeding, a broken rib and shattered left knee when he was struck by a lorry on the A64 near York on 22 December.
Afterwards he said he had been left severely depressed by the end of his football career, financial problems and the loss of a TV punditry role.
He left hospital six weeks after being struck, following treatment as an in-patient at a psychiatric unit.
A former chairman of players' union the Professional Footballers' Association, he added:  "I'm managing my illness on a daily basis and I can tell you today I'm very well."
The first footballer to appear on Question Time, Carlisle had previously spoken out about depression and suicide in professional sport and presented a BBC Three documentary on the subject.
On Monday, he pleaded guilty to failing to provide a sample to police on 20 December, at London's Highbury Corner Magistrates' Court, and will be sentenced on 14 May.
Former defender Clarke Carlisle has said he feels "no shame" about his recent suicide attempt.