BEWARE OF SPOILERS! To prevent the page from being whited out entirely, only spoilers from the final season (5) are whited out!
- Team Machinenote John Reese, Harold Finch, Joss Carter, Lionel Fusco, Sameen Shaw, Root, Bear, The Machine, Mr. Rick Dillinger
- Friends & Alliesnote Nathan Ingram, Zoe Morgan, Grace Hendricks, Jessica Arndt, Leon Tao
- Persons of Interestnote Diane Hansen, Theresa Whitaker, Bill, Joey Durban, Megan Tillman, Samuel Gates, Zoe Morgan, Charlie Burton, Ulrich Kohl, Joss Carter, Wendy McNally, Paula Vasquez, Matt Duggan, Claire Ryan, Ernie Trask, Andrea Gutierrez, Scott Powell, Darren McGrady, Michael Cahill, Adam Saunders, Leila Smith, Gianna Moretti Sr, Jordan Hester, Gianna Moretti Jr, Tommy Clay, Sarah Jennings, Henry Peck, Caroline Turing, Leon Tao, Hanna Frey, Sofia Campos, Riley Cavanaugh, Maxine Angelis, Graham Wyler, Madeleine Enright, Daniel & Sabrina Drake, Fermin Ordoñez, Abby Monroe, Caleb Phipps, Karolina Kurkova, Logan Pierce, Mira Brozi, Michael Cole, Lou Mitchell, Monica Jacobs, Richard Nelson, Jack Salazar, Wayne Kruger, Ian Murphy, Rachel Jensen, Vanessa Watkins, Genrika Zhirova, Timothy Sloan, Jason Greenfield, Hayden Price, Arthur Claypool, Owen Matthews, Kelli Lin, Sandra Nicholson, Haley McNabb, Daniel Casey, Cyrus Wells, Maria Martinez, Leona Wainwright, Matthew Reed, Ali Hasan, Claire Mahoney, Andre Cooper, Malcolm and Tracie Booker, Simon Lee, Walter Dang, Tomas Koroa, Dani Silva, Yasin Said, Emma Blake, Anna Mueller, Harper Rose, Shane Edwards, Frankie Wells, Sulaiman Khan, Chase Patterson, Laurie Granger, Gerald Mancini, Alex Duncan, Ethan Garvin, Phoebe Turner, Max Greene, Vasily Mikhaev, James Ko, Terry Easton
- Law Enforcementnote Captain Moreno, Iris Campbell, Dani Silva, Cal Beecher, Bill Szymanski, Nicholas Donnelly, Brian Moss, Mark Snow, Tyrell Evans
- Northern Lightsnote Control, Pennsylvania Two/Special Counsel, Ross Garrison, Hersh, Alicia Corwin, Denton Weeks
- Antagonistsnote Peter Collier, Jefferson, Ronald Carmichael, Peter Arndt, Byron, Alistair Wesley, The Voice, IRS, Andrew Benton, Jarek Koska, Brad Jennings, George Massey, Alex Declan, Dario Makris
- Decima Technologies & Samaritannote Samaritan, John Greer, Kara Stanton, Lambert, Martine Rousseau, Claire Mahoney
- Crime Organizationsnote Carl Elias, Scarface, Gianni Moretti Sr, Gianni Moretti Jr, Peter Yogorov, Ivan Yogorov, Lazslo Yogorov, Dominic, Link, Floyd
- HRnote Alonzo Quinn, Patrick Simmons, Raymond Terney, Mike Laskey, Artie Lynch, Louis Azarello, Jimmy Stills, Diane Hansen