"I don't think you'll find any prisoner who will complain about Greenock jail.
Mr Sheridan was speaking on his release from Greenock Prison after serving five days of a 14-day sentence.
The 36-year-old Glasgow list MSP was jailed for refusing to pay a £250 court fine.
Sporting a T-shirt with the slogan "Scotland Nuclear Free" emblazoned across the front, he said he hoped he had put the issue of nuclear weapons back on the political map.
He was greeted with a kiss from his wife, Gail, and said he had been treated well.
He said that conditions were "markedly better" than during his last stint in jail in 1992.
On that occasion he was imprisoned in Edinburgh for breaching a court order which banned him from attending a warrant sale.
He said: "It was cold, but that's probably to do with the fact that I'm parliamentarily pampered most of the time.
"I would say conditions have changed markedly for the better since I was in Saughton.
"I don't think you'll find any prisoner who will complain about Greenock jail.
"Prison is obviously tough, but the regime itself was relatively humane and the prisoners and prison officers treated me with a great deal of respect.
"I hope that what we have managed to do is to put nuclear disarmament back on the political agenda in Scotland.
"Certainly on 12 February next year there will be a big turn out of peace protesters fighting for the disarmament of nuclear weapons and a war on poverty rather than a war on ordinary human beings."
Mr Sheridan was convicted at Argyll District Court in Helensburgh last month following an anti-nuclear protest at the Faslane Trident submarine base on 14 February.
He was told that if he failed to pay the fine he would spend 14 days in jail.
The MSP handed himself in at Dumbarton police station on Sunday, two days after a warrant was issued for his arrest.