The blanket ban, known as the Criminal Justice Psychoactive Substances Act, was introduced five years ago.
Before the law was passed, there were about 100 so-called "headshops" selling legal highs across the state, but that number has since been reduced to zero.
"The headshop industry is gone," Det Supt Tony Howard told the BBC.
He is a member of the Garda (Irish police) Drugs Unit, which has been responsible for enforcing the new legislation.
"We were worried because we saw a whole generation of young people starting to experiment with these new psychoactive substances, and they'd generally be people who wouldn't have otherwise engaged in the misuse of drugs," he said.
"They thought it was safe because of the perception that these were legal highs."
When the blanket ban took effect, it became illegal to advertise, sell, supply, import or export psychoactive substances in the Republic of Ireland.
Tobacco, alcohol, caffeine and medicines have been excluded from the ban.
Before the legislation came into force, the sale of legal highs appeared to be a very lucrative business.
When one Dublin city centre headshop was burnt down in an arson attack, firefighters found a safe in the charred rubble of the building that contained 450,000 euros (Â£330,000).
As the sale of psychoactive substances was not illegal at the time, police had to hand the cash back to the owner of the safe.
As a result of the ban, that would not happen now.
Det Supt Howard said many of those who operated the headshops quickly complied with the new law.
"Essentially the industry themselves realised that the legislation was quiet strong and they actually co-operated with us and handed us over any residual product which they had," he said.
So, should the UK follow the Irish government's lead and outlaw legal highs?
It may have taken the headshops out of the high street but not everyone believes the ban is the most effective way to protect drug users.
Tony Duffin, director of the Ana Liffey Drug Project in Dublin said there was still "huge harm" associated with the substances formally sold by headshops.
He said many recreational users are now buying psychoactive substances over the internet instead, and more regular users just go to drug dealers.
"I'm aware that, in New Zealand, they are currently rolling out legislation to regulate headshop drugs.  So I think that, in terms of the UK, they would do well to look at all the options on the table in terms of drug policy," Mr Duffin said.
"It's not always about prohibition."

Five-time world champion O'Sullivan took the first three frames and won 4-1 after White had beaten Ryan Day without losing a frame.
Home favourite Higgins beat compatriot Scott Donaldson and fellow Scot Stephen Maguire defeated Fergal O'Brien.
Neil Robertson and Judd Trump were among Wednesday's other winners.
Robertson overcame Gary Wilson, while Marco Fu beat Liam Highfield and Trump defeated Igor Figueiredo, with Ali Carter losing to Chris Wakelin.
Scots Graeme Dott and Anthony McGill lost to Mark Davis and Mitchell Mann, respectively.
Mei Xi Wen eliminated Peter Ebdon and will play four-time world champion Higgins on Thursday.
Trump will face Noppon Saengkham and Robertson takes on Joe Swail.
The latest event in the Home Nations Series, the tournament is the first World Snooker ranking event held in Scotland since the World Open in 2010.
A ban on "legal highs" in the Republic of Ireland has been extraordinarily effective in wiping out the industry, police have said.
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Ronnie O'Sullivan beat Adam Stefanow to set up a third-round tie against Jimmy White at the Scottish Open, as John Higgins also progressed in Glasgow.