The numerous actors who have roles in both DC and Marvel films and television series are listed in full below. Despite the fact that they all appeared in The Spirit and the MCU (as well as Ghost Rider, in the latter), you won't find Samuel L. Jackson, Eva Mendes, or Scarlett Johansson on it.
1. Randall Park
Source: Marvel Studios/Disney; 20th Century Fox;
Randall Park played Dr. Stephen Shin in "Aquaman," despite his reputation in the MCU for handing out card tricks.2. Jon Favreau
Source: Marvel Studios/Disney; 20th Century Fox;
Before becoming Tony Stark's aide and buddy Happy Hogan in the MCU, Jon Favreau worked as one of Bruce Wayne's helpers.3. Tilda Swinton
Source: Marvel Studios/Disney; 20th Century Fox;
After her performance in "Constantine," Tilda Swinton took on the character of a gender-flipped Ancient One in "Doctor Strange."4. Rachel Weisz
Source: Marvel Studios/Disney; 20th Century Fox;
Years after making an appearance in "Constantine," Rachel Weisz also joined the MCU.5. Ben Mendelsohn
Source: Marvel Studios/Disney; 20th Century Fox;
Before playing the amiable Skrull Talos that we now know and love, Ben Mendelsohn had an appearance in "The Dark Knight Rises."6. Zachary Levi
Source: Marvel Studios/Disney; 20th Century Fox;
Before taking the lead in DC's "Shazam!", Zachary Levi was a close buddy of Thor.7. Jared Leto
Source: Marvel Studios/Disney; 20th Century Fox;
After portraying DC's most recognizable Batman villain, Jared Leto is now a Marvel vampire.8. Christian Bale
Source: Marvel Studios/Disney; 20th Century Fox;
After appearing in "The Dark Knight" trilogy, Christian Bale is now portraying a villain in the MCU.9. Sean Gunn
Source: Marvel Studios/Disney; 20th Century Fox;
In both the DC and MCU universes, Sean Gunn performs dual roles.10. Michael Rooker
Source: Marvel Studios/Disney; 20th Century Fox;
Additionally, Michael Rooker may be seen in "The Suicide Squad" and the "Guardians of the Galaxy" series.11. Sylvester Stallone
Source: Marvel Studios/Disney; 20th Century Fox;
Sylvester Stallone appeared in both the Marvel and DC movies directed by James Gunn.12. Pom Klementieff
Source: Marvel Studios/Disney; 20th Century Fox;
Pom Klementieff's brief appearance in "The Suicide Squad" could be missed.13. Laurence Fishburne
Source: Marvel Studios/Disney; 20th Century Fox;
Laurence Fishburne was Lois Lane's editor in the DCEU prior to doing experiments in the MCU.14. Djimon Hounsou
Source: Marvel Studios/Disney; 20th Century Fox;
Djimon Hounsou has portrayed three other DC characters in addition to Korath in the MCU.15. Adewale Akinnuoye-Agbaje
Source: Marvel Studios/Disney; 20th Century Fox;
In his work for Marvel and DC, Adewale Akinnuoye-Agbaje has appeared very different.16. Tommy Lee Jones
Source: Marvel Studios/Disney; 20th Century Fox;
In "Captain America: The First Avenger," Tommy Lee Jones played a colonel. But he portrayed one of Batman's most infamous enemies more than ten years prior.17. Barry Keoghan
Source: Marvel Studios/Disney; 20th Century Fox;
Barry Keoghan, who portrayed Druig in "Eternals," is currently "The Batman's" newest Joker.