Juncker's State of the EU address to the Strasbourg body will be the last before May elections that will pit Europe's rising populist forces against his centrist supporters -- but aides insist it will not be his swansong.
Instead, he is expected to announce plans to recruit 10,000 EU border control officers and take a tough line on Europe's priorities in Brexit negotiations with London.
He will also broach the topic of decreasing the use of the US dollar in energy contracts, diminishing Washington's financial influence.
"In the final straight we are determined to follow the golden rule in politics. When you have a political mandate, you start strong and you finish strong," EU spokesman Margaritis Schinas said in the run up to the speech.
According to a European diplomat, Juncker knows it is a "critical" moment to prepare Europe for a world in which President Donald Trump's United States is an unpredictable foreign policy friend and a protectionist trade rival.
Despite the rising challenge of populist, nationalist parties in Europe -- chafing at EU rules on immigration and the rule of law -- Juncker wants Brussels to take a more influential role on the international stage.
- Belonging together -
The set-piece speech will be Juncker's fourth such state of the union. He leaves office on October 31 next year after a term marked by crisis after crisis: a refugee influx, soaring debt and Britain's divorce demand.
Populist, nationalist and eurosceptic forces have gained ground in many countries, and the European parliamentary elections in May could well bring in more of Juncker's opponents to rock the boat just as he tries to consolidate what he sees as real successes in restoring forward momentum to the European project.
"The crisis we feel, is a crisis of fellow-feeling, of belonging together," warned Philippe Lamberts, co-president of parliament's Green group.
And Social Democrat leader Udo Bullman said, ahead of the speech: "We will insist on a clear answer to the crises. Business as usual is not an option."
After Juncker lays out his proposals, including new measures to better divide responsibility for coping with new refugee and migrant influxes, parliament must turn these into legislation and then national governments must approve.
In total, the former Luxembourg prime minister is expected to lay out 18 propositions or initiatives. The speech was due to begin at 0700 GMT.