Mark Strong will soon be seen in Shazam! playing the movie's villain, Doctor Sivana. However, this is the actor's second shot at playing a major role in a DC Comics superhero movie. Back in 2011 Strong played the role of Sinestro in the Ryan Reynolds-led Green Lantern. That movie was one of the few recent failures when it comes to superhero movies at the box office. If the movie had been a hit, we would have seen a lot more of Mark Strong in a sequel, but that movie never happened, something Mark Strong is still a bit upset about. According to the actor...
I loved Sinestro because I always thought if we can really manifest that guy, a look for that guy as he is in the comics, that would just be insane. I love the fact that he looked the way he did, and I really enjoyed it, and it was such a shame to me that movie didn't kick in, you know, because I thought that part was great.
When we meet Sinestro in Green Lantern, he's the leader of the Green Lantern Corps when Ryan Reynolds' Hal Jordan finds himself somewhat unwittingly drafted. In the end, Sinestro believes the only way to fight the villain Paralax is with the power of fear, and he has a power ring forged that gives him that power. In the post-credits scene of the movie, we see Sinestro putting on the yellow ring and its power seems to overwhelm him.
If a Green Lantern sequel had happened, we almost certainly would have seen Green Lantern's greatest enemy, Sinestro, take center stage. Clearly that was part of the plan for bringing Mark Strong in to play the role in the first place. You don't cast somebody like him in a simple supporting role.
Mark Strong was certainly on board for the long term plan. It sounds like he still is, as he tells ComicBook.com that's still bummed he didn't get a chance to play the part at the level he knew it was capable of.
While Green Lantern was certainly a movie with some issues. Few would lay any of the movies problems at the feel of Mark Strong. He was a perfectly good SInestro and probably would have been a fantastic villain if the sequel had ever actually happened.
It did not, but now Mark Strong will have his second bite at the comic book villain apple in the form of Doctor Sivana. He'll be the force opposing Zachary Levi/Asher Angel as Shazam. The trailers have largely kept our villain under wraps, so we don't really know what to expect, but we can pretty much always count on Mark Strong to bring the energy necessary to be a great comic book supervillain.
As far as the future of Green lantern goes, plans for a new Green Lantern film set within the DC film universe have been announced, but momentum on that project is either moving very slowly, or not at all, as we've heard little to indicate we'll be seeing a new Green Lantern anytime soon.