* ActorAllusion: This isn't the first time Robson Green (Colonel Locke) plays a soldier; his StarMakingRole was as Fusilier Dave Tucker on Soldier Soldier.
* FakeNationality: Both the Cinemax leads. Specifically:
** FakeBrit: Stonebridge, played by Philip Winchester (American).
** FakeAmerican: Scott, played by Sullivan Stapleton (Australian).
** Karl Matlock is also a FakeAmerican, played by Irish actor Vincent Regan.
** Pakistani terrorist Latif is played by British actor Jimi Mistry, whose parents are Irish and ''[[{{Irony}} Indian]]''.
* HeyItsThatGuy:
** Given the obscurity of Series/ChrisRyansStrikeBack outside of Britian, Creator/RichardArmitage's appearance as Porter may count as this to American audiences.
** Hugh Collinson eventually became [[Series/TheWalkingDead a sheriff fighting to survive a zombie apocalypse]].
** [[Series/{{Arrow}} Walter Steele]] is a liaison between Section 20 and the government.
** [[{{Series/Lost}} Mr. Eko]] held [[Series/GameOfThrones Ser Jorah Mormont's]] daughter ransom for guns in ''Project Dawn'', episodes five and six.
** [[Series/GameOfThrones Tywin Lannister]] is ''Vengeance'''s BigBad, and is up to his usual trick of manipulating the geopolitical climate for his own benefit.
** [[{{Film/Underworld}} Sonja]] was in charge of Section 20 during ''Vengeance'' and the beginning of ''Shadow Warfare''.
** DocMartin appears as a retired MI-6 officer living in Beirut.
** [[WireInTheBlood Dr. Tony Hill]] is Section 20's new boss, replacing Dalton.