The 33-year-old French veteran, on his ninth participation in the Grande Boucle, had returned to competition late after a domestic accident in February.
But all his catching-up work paid off as he relegated fellow stage contender Ludo Dierckxsens of Belgium to second place as the Tour made its way over 215K back into France from Huy in Belgium.
"I never let up today," said Jalabert. "I've still got a sore back and I've had a few doubts lately it's but this victory has helped to get rid of some of those."
Australian Stuart O'Grady keeps the yellow jersey.
On what would turn out to be a tactically-tricky stage, an early breakaway attempt was made as early as the 10km mark, with the first major casualty of the 215km stage retiring quickly.
Italy's former world number one Francesco Casagrande, left struggling behind the peloton on Tuesday as he nursed a fractured wrist from a crash in the Giro d'Italia. His Fassa Bartolo team was left to soldier on without their commander.
But attention soon turned to a nine-man group which escaped the peloton, with the on-form Bobby Julich only 21secs off his teammate and race leader Stuart O'Grady's pace prior to the stage leading the attack.
American Julich, of the Credit Agricole team, and his cohorts left Tour favorite Lance Armstrong of US Postal with a 10-minute gap to close after they had pushed hard over the three successive category four climbs.
But the unwritten rules of riding the Tour soon brought their audacious bid under control.
The peloton behind the 30-year-old Julich then split up, leaving Armstrong's team to work hand-in-hand with the Spanish ONCE team to try and reduce the deficit, a tactical maneuver which could have gone against Armstrong if ONCE refused to play ball.
But by the 125K mark, their combined efforts paid off, with Julich soon reeled in by Armstrong's chasing group.
That included Germany's co-Tour favorite Jan Ullrich of Telekom in the white jersey of German national champion yellow jersey O'Grady, former yellow jersey Christophe Moreau of Festina and last year's third place finisher Joseba Beloki of Spain.
They held a 1:05 gap over the second peloton from which Axel Merckx and the Tour's youngest rider Sylvain Chavanel, 22, were struggling to escape.
Armstrong won his first Tour de France stage here in a Motorola shirt way back in 1993, when he beat aggressive Irishman Stephen Roche to the line, and it looked that he might be going for a repeat performance.
As the American maintained a much faster pace in the leading pack, the only Briton in the race David Millar continued to struggle with his injured knee and dropped off the back.
The 24-year-old Scot crashed in Saturday's prologue and was further pained by being left in among the team cars as he pushed to join the group.
At the other end the pink jerseys of the Telekom team, so impressive on Tuesday when they lead Zabel in for his sprint victory, battled alongside ONCE and US Postal.
But in doing so, they left green jersey holder Zabel behind, leaving O'Grady with a chance to make up his 30-point deficit on the big German in the quest for points.
At 35K from the finish the 45-man leading group was caught by the second peloton, and both stayed together until iBanesto's Francisco Mancebo last year's white jersey winner was joined by Jalabert and Dierckxsens in a three-pronged attack.
Jalabert, who admits he has no great designs on having a glorious Tour, defied those claims to attack three kilometers from the finish. But he was soon joined by fellow veteran Dierckxsens, with Francaise des Jeux rider, Emmanuel Magnien giving chase from the peloton.
Jalabert and Dierckxsens had done enough to lose the rest of the peloton, with the Frenchman sitting on the Belgian's wheel.
Jalabert, who last won a Tour stage in Mende in 1995, timed his attack perfectly, and proved the hungrier rider as he came over the line ahead of his 37-year-old rival.
Stage 4 results: Huy to Verdun (215K)
1. Laurent Jalabert, France, CSC-Tiscali, five hours, 17 minutes and 49 seconds.
2. Ludo Dierckxsens, Belgium, Lampre, same time
3. Damien Nazon, France, Bonjour, at +:07
4. Fred Rodriguez, United States, Domo Farm Frites, same time
5. Alessandro Petacchi, Italy, Fassa Bortolo, s.t.
6. Sven Teutenberg, Germany, Festina, s.t.
7. Robert Hunter, South Africa, Lampre, s.t.
8. Stuart O'Grady, Australia, Credit Agricole, s.t.
9. Paul Van Hyfte, Belgium, Lotto, s.t.
10. Sebastien Talabardon, France, BigMat Auber 93, s.t.
11. Francois Simon, France, Bonjour, s.t.
12. Steffen Wesemann, Germany, Team Telekom, s.t.
13. Serge Baguet, Belgium, Lotto, s.t.
14. Stefano Zanini, Italy, Mapei, s.t.
15. Marc Lotz, Netherlands, Rabobank, s.t.
Complete results of Stage 4
Overall standings after Stage 4:
1. Stuart O'Grady, Australia, Credit Agricole, 19:32:49.
2. Laurent Jalabert, France, CST, 00:18.
3. Christophe Moreau France, Festina, 00:23.
4. Jens Voigt, Germany, Credit Agricole, 00:26.
5. Igor Gonzalez Galdeano, Spain, ONCE, 00:26.
6. Bobby Julich USA, Credit Agricole, 00:27.
7. Lance Armstrong , USA, US Postal, 00:27.
8. Jan Ullrich, Germany, Telekom, 00:30.
9. Florent Brard, France, Festina, 00:30.
10. Santiago Botero, Colombia, Kelme, 00:33
Complete overall standings after Stage 4