Federal Judge Sergio Moro on Wednesday sentenced Jose Dirceu to 23 years and three months in prison.
"Not even a conviction by the country's highest court could inhibit criminal relapse," Moro wrote in his sentencing decision.
Prosecutors argued that Dirceu had masterminded a kickback scheme at Petrobras - aka Petroleo Brasileiro - and also accepted bribes while in office. He had, the judge accepted, also continued to receive payments from contractors after he was jailed in late 2013 for a vote-buying scandal.
The sentence can be appealed.
Another 10 people were sentenced, including Workers' Party former treasurer Joao Vaccari Neto, who was given nine years in prison. Others facing investigation include members of the new government headed by acting president, Michel Temer, who took over from President Dilma Rousseff after her suspension last week.
'Operation Car Wash'
Moro - who is presiding over the Petrobras investigation (aka "Operation Car Wash") that has involved some of Brazil's richest business people and public figures from all parties - heard prosecutors' claims that over $2 billion (1.78 billion euros) was paid in bribes and other funds by Brazil's largest construction and engineering firms in exchange for inflated Petrobras contracts.
The mighty fall
Dirceu served under ex-President Luiz Inacio Lula da Silva between 2003 and 2005. He is the most senior member of the Workers' Party - which governed Brazil from 2003 until last week - to be arrested in connection with the case.
Brazil's Senate suspended Rousseff, Lula's hand-picked successor, last week pending the outcome of a trial in the chamber for violating budget rules. This opened the way for Temer's apparently more business-friendly government to take power on an interim basis.
The investigation is Brazil's biggest ever and has led to the imprisonment of business executives and politicians. It has also stirred up public outrage in turn contributing to the impeachment process against Rousseff, who has not been accused of wrongdoing as part of the Petrobras case.
Both Lula and Rousseff deny they have done anything wrong.
Back in the halcyon days
Lula founded the Workers Party with Dirceu and other left-wing activists in the 1980s.
jbh/rc (AP, Reuters, AFP)