Can Superman Lift Thor's Hammer?
Comics fans know that Thor Odinson is far from the only one to have wielded his hammer, Mjolnir. At various points in Marvel lore, characters as varied as Captain America, the alien cyborg Beta Ray Bill, and even Loki have been found "worthy" of wielding the weapon, but crossover-minded fans have always been curious as to whether a certain icon of the Distinguished Competition could wield Mjolnir: the Big Blue Boy Scout, Superman.
If there's any DC character one would think might stand a chance of being worthy, it's Supes. In most depictions, anyway, the hero is an absolute beacon of virtue — fair-minded, possessed of a strong sense of duty to watch out for the little guy, and unwilling to even think about using his immense power for anything other than protecting the innocent and thwarting evil. So, if Superman were to happen to come across Thor's legendary weapon — which famously is immovable to those unworthy of its might — could he lift it? Well, the answer to that question is simple: he can, and he has.
This occurred in the fourth issue of the Avengers/JLA crossover event, in a story titled "The Brave and the Bold," published in December 2003. Check out this image, which was used for one of the issue's variant covers, and which depicts Big Blue wielding not only Mjolnir, but Captain America's shield — making him the only character in comics history besides Cap himself brandish both of the iconic weapons at once.
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The story involved the catastrophic near-merging of the mainstream Marvel and DC universes due to a contest being held between the Grandmaster and Krona, a supremely powerful being seeking the secrets of creation. As minions of the two entities were overwhelming the combined might of the Justice League and the Avengers, Thor — who had fought Superman to a standstill two issues earlier — had a wild idea for an emergency course of action.
He threw Mjolinir to Superman, who was already in possession of Cap's shield, shouting, "Do thou well with it!" Superman did just that; although the power of Thor temporarily threatened to overwhelm him, he was able to gain control of it, and promptly went on the kind of world-shattering tear one would expect from Superman wielding Mjolnir (and, therefore, all of Thor's considerable power in addition to his own).
Supes was then able to defeat Krona and put an end to the threat of the merging universes, but an even more satisfying moment — for Marvel fans, anyway — lay in store after the big battle was won. Superman attempted to casually pick up Mjolnir and return it to Thor, but found that he could not. Thor remarked that, whaddaya know, Odin must have lifted the enchantment on a temporary basis to allow the heroes to prevail — so while Superman may have been worthy, he wasn't you know, that worthy.
Interestingly, Big Blue is not the only prominent DC character to have wielded Mjolnir — Wonder Woman did it first. In the 1996 DC vs. Marvel crossover event, heroes from each imprint were pitted against each other in battle, with readers voting on the outcome of each fight. During the final issue of the four-issue series, Thor has temporarily separated from his hammer, and it was happened across by Wondy — who wielded it effortlessly, and seemed prepared to use it to take on Storm of the X-Men.
Diana's unwillingness to engage in anything other than a fair fight sealed her loss, however; after feeling the power of Thor course through her, she determined that said power gave her an unnecessary edge over her opponent. So, she simply dropped it, then proceeded to get her Amazonian butt kicked by Storm. For this outcome, Wonder Woman had the readers to thank — the X-Men were all the rage among comics fans in the mid-'90s, and they had voted in droves for Storm as the victor in that particular battle.
So, there you have it: yes, Superman is capable of wielding Mjolnir, although he was only seen to have done so on an emergency basis — and, in fact, it appears that Wonder Woman is more unconditionally worthy of the weapon than he. Marvel and DC have a long history of crossover events, but we submit that one more may be necessary in order to settle the question of Supes' worthiness once and for all.