The man, wearing a builder's hard hat and a yellow fluorescent coat, raised himself to a height in the cage, where he remained for more than an hour, using a loudspeaker to play the hit single Poker Face by Lady Gaga and the theme from the spaghetti western The Good, The Bad And The Ugly.
The control panel was sealed off, preventing gardai from bringing the protester back to the ground.
The man lowered the crane arm at around 8.45am and was arrested by half a dozen officers, who bundled him into the back of a garda van.
The man was taken to Pearse Street Garda Station, in the city centre, and detained under Section 4 of the Criminal Justice Act.
In a statement, the Houses of the Oireachtas said the protest would not disrupt the day's crucial Dail (parliament) business.
"There is no disruption to pedestrian or vehicle access to Leinster House and proceedings will continue as normal throughout the day," it read.
The move is one of a string of protests by people angry at the Government's handling of the economic crisis.
A property developer was accused of blocking the entrance to Leinster House in a cement truck in late September in protest at his treatment by the banks. Joe McNamara was released on bail after being charged at Dublin District Court with criminal damage.
Authorities were preparing for a day of demonstrations, with left-wing groups, students and community organisations all planning to picket the area.
Security was tight, with crash barriers and crowd control plans in place at Leinster House and also Government Buildings.
© Press Association