Christy Kinahan, dubbed the "Irish Godfather", was detained with his two sons on the Costa del Sol as authorities in Britain, Ireland and mainland Europe moved in on underworld associates.
The 53-year-old, born in Britain but brought up in Dublin, is alleged to be the kingpin of a £200m crime network which traded in drugs and guns, and laundered dirty cash for Europe's top gangsters.
The outfit has direct links to South American cartels, gangs in most of the major cities in the UK and has associates in the Netherlands, north Africa, Russia and Turkey.
The Serious Organised Crime Agency (Soca) and Irish authorities described it as a prolific crime empire.
Garda Commissioner Fachtna Murphy said there is "no hiding place" for drug smugglers.
"People go to the sun, or hide in the sun, or hide in some foreign clime and think the border can help them to conceal their ill-gotten gains in trafficking drugs," the Commissioner said.
"The message from today's operation is clear: there is no hiding place for those who seek to bring misery and hurt to communities here in Ireland and abroad.
"If people choose to trade drugs and death across borders, police will work together across those same borders to address that challenge and disrupt criminal activity."
Trevor Pearce, Soca executive director, said: "We also believe this network has been offering a global investment service, ploughing hundreds of millions of pounds of dirty cash into offshore accounts, companies and property on behalf of criminals.
"A financial investigation is already under way."
Kinahan's suspected right hand man, John Cunningham, who was convicted over the 1986 kidnap of heiress Jennifer Guinness in Ireland, was arrested along with at least two dozen others.
Four lawyers were detained in Spain as part of Operation Shovel as police recovered false passports and €60,000 in cash, seized computers and 20 luxury cars - some from the €6m mansion where Kinahan was holed up near Malaga, an area of the Costas notorious for links to crime. The next move could see scores of bank accounts frozen.
Raids were also carried out in Belgium, Cyprus and Brazil.
In the UK, about 230 officers arrested nine men and two women as they searched business and residential premises in London, the Thames Valley, Kent and the West Midlands. Firearms and £70,000 were recovered.
Five Britons were detained in Spain.
A senior security source in the two-year investigation warned: "The impact of the gang has been felt harder in the UK in the last while. Most of the drugs and the guns have been hitting the gangs in British cities."
In Ireland one man was arrested after 29 searches on homes and businesses in Dublin and neighbouring Co Meath.
Irish Justice Minister Dermot Ahern said: "The fact is that no border will protect those involved in organised crime.
"Today's events are evidence of the determination of those involved in law enforcement, fully supported by their governments, to take international gangs straight on."
Kinahan can be held in Spain for about one year without charge as an investigating judge examines the case against him.