Thor has become unworthy of using the Mjolnir in both the Marvel Cinematic Universe and Marvel Comics, but for very different reasons. The god of Thunder’s debut in the MCU centered around his exile to Earth as a mortal and his unworthiness to wield the Mjolnir. In the comics, this was explored deeper, even getting a limited series literally titled The Unworthy Thor.
Thor’s worthiness and ability to use the Mjolnir was a central theme in his introduction to the MCU, with audiences eventually learning that anyone worthy of it can lift the hammer, such as Vision in Avengers: Age of Ultron and Captain America in Avengers: Endgame. This is pretty much the same in the comics: only those worthy of it will be able to lift it, but the reason behind Thor’s unworthiness had nothing to do with arrogance.
During the events in the Original Sin storyline in 2014, Nick Fury, with the powers of the Watcher, whispered something to Thor that caused him to lose the ability to use the Mjolnir, making way for another worthy character that soon took the name (and powers) of Thor: Jane Foster. After this, Thor continued his journey under the name “Odinson”. Fury’s words weren’t revealed until the limited series The Unworthy Thor in 2016, and with them what truly made Thor not being able to lift the hammer anymore.
Fury’s words were “Gorr was right,” which connect with Thor, God of Thunder, where Gorr the God Butcher goes after the Gods as he believes they have forgotten to help those in need and, because of that, they should die. With this, Thor realized that he and the rest of the Gods are not worthy of admiration as they are “vain and vengeful creatures”, making it impossible for him to use the hammer. Prior to that revelation, Odinson had the chance to take the Ultimate Mjolnir but decided not to, instead channeling the power of it to return Asgard to its rightful place after the events in Secret Wars, with the help of Beta Ray Bill. After keeping the hammer away from the Collector and saving Asgard, Odinson would have most likely been worthy again, but these actions wouldn’t have changed his situation that much if he still found himself unworthy not only of the hammer but of the love and admiration of mortals and his overall role as a God.
With Thor: Love and Thunder officially part of the MCU’s Phase 4, and Natalie Portman coming back as Jane Foster and taking on the role of Thor along with Chris Hemsworth, it’s clear that Marvel Studios is taking some ideas from the events in Original Sin and The Unworthy Thor to make the change. What’s unclear, however, is whether they will make Thor Odinson unworthy, perhaps instead proving that Foster has the qualities that make a person worthy of using the hammer. After all (and as mentioned above), Vision and Captain America were able to use it while Thor was worthy.
Next: Thor’s New Mjolnir Is More Powerful Than Ever Before