Lord Falconer says it is "ridiculously overdone" to claim free speech is being undermined after the arrest of a woman for listing the UK's Iraq war dead.
Ms Evans was tried at Bow Street Magistrates' Court
Maya Evans, 25, recited the 97 names by the Cenotaph memorial to Britain's war dead in Whitehall, near Downing Street.
She was found guilty of breaking a new law stopping unauthorised protests within half a mile of Parliament.
The lord chancellor said the law was a "sensible" precaution to stop disorder rather than an attack on free speech.
Ms Evans, a vegan cook from Hastings, was given a conditional discharge and ordered to pay £100 costs after being found guilty of breaching the Serious Organised Crime and Police Act 2005.
Critics claim the move was over the top for what was seen as a peaceful protest.
They also accuse the government of clamping down on freedom of speech.
Asked about the case on BBC Radio 4's Today programme, Lord Falconer said: "Freedom of speech is alive and well in this country. We are a country which could not be freer in its press, in what we say.
"The idea that we take a measure, which is a public order measure, designed to protect our Parliament building, as depriving us of freedom of speech is ridiculously overdone.
"There isn't a country in the world that doesn't take particular measures to protect its Parliament."
The new law was initially intended to remove Brian Haw, an anti-war protester who has camped in Parliament Square for four years.
But Mr Haw successfully fought off the latest attempt to evict him in the High Court, by arguing his protest pre-dated the legislation.