The Toulouse back-rower suffered a torn ACL in France’s 32-21 Six Nations win over Scotland in Paris in February.
Jelonch went under the knife in March, and just six months later will lead Les Bleus in their second Pool A clash with Uruguay.
Head coach Fabien Galthie has rotated resources from the opening-night win over New Zealand, to keep France’s squad fresh and firing.
For Jelonch, the chance to feature in a home World Cup kept his rehab on course through several testing months.
“I had my doubts at the start of my rehab, but I knew I had six months,” said Jelonch. “I worked very hard in those six months and gave myself the chance to come back.
“To return as captain is a huge source of pride and I’ll do everything I can to lead my team-mates to victory. I had my operation six months ago. My knee is holding up well and I’ve got the green light from the surgeons and physiotherapists.
“I’ve been preparing for a few weeks now. Fabien said to me ‘you choose the match you want to play’. I felt ready and he told me I could play this week. I’m just looking forward to kick-off now.”
France boss Galthie has made 12 changes to the starting lineup from Friday night’s 27-13 win over New Zealand in Paris.
The hosts will face Namibia and Italy after Thursday’s Uruguay clash, in what ought to be a straightforward Pool A programme after that win over the All Blacks.
Cameron Woki, Gabin Villiere and Yoram Moefana are the three to retain their starting berths, while Jelonch captains France for the first time since 2021.
Galthie hailed Jelonch’s return as a major boost to his playing resources – but also to France’s squad morale.
“We remember that night against Scotland, we’d won, but it was tough for the group because we knew Anthony was injured,” said Galthie.
“He represents the group perfectly. We’ve sometimes been hit hard, we’ve lived through difficult times in terms of the game, adversity and the environment.
“But the group has always stood together and the players have been strong, and that’s where our strength lies: in determination, confidence and solidarity.”