In film, television, and theatre, typecasting is the process by which a particular actor becomes strongly identified with a specific character, one or more particular roles, or characters having the same traits or coming from the same social or ethnic groups. There have been instances in which an actor has been so strongly identified with a role as to make it difficult for them to find work playing other characters.

Character actors Actors are sometimes so strongly identified with a role as to make it difficult for them to find work playing other characters. It is especially common among leading actors in popular television series and films.

Star Trek One example of typecasting occurred with the cast of the original Star Trek series. Parade stated of the cast, "They are 'stars' only in the world of Star Trek ... [They] lost control of their destinies the minute they stepped on the bridge of the make-believe Enterprise in 1966", and The New York Times observed in 1991 that "For most of the actors in the original "Star Trek" series, Starfleet has never been far off the professional horizons".

During Star Treks original run from 1966 to 1969, William Shatner was the highest-paid cast member at $5,000 per episode (equivalent to $ in ), with Leonard Nimoy and the other actors being paid much less. The press predicted that Nimoy would be a star after the series ended, and James Doohan expected that appearing on an NBC series would help his post-Star Trek career. The series typecast the actors, however. As early as March 1970, Nichelle Nichols complained of Star Trek having "defined [her] so narrowly as an actress", and Doohan said that by 1971 producers were calling him "Scotty" when turning him down for roles, with even those he worked with before Star Trek telling his agent "I don't want a Scotsman". Only Shatner and Nimoy continued working steadily during the 1970s, and even their work received little attention unless it was Star Trek-related.

Walter Koenig in 1976 noted the disparity between the adulation from Trekkies at Star Trek conventions and his obscurity in Hollywood. Residuals from the series ended in 1971; Koenig, Doohan, and DeForest Kelley discussed the paradox of starring in what Kelley described as "the most popular series in the world" because of reruns, but "not getting paid for it". Cast members' income came mostly from personal appearances at conventions; by 1978 Kelley, for example, earned up to $50,000 (equivalent to $ in ) annually. In 1979, the first of six films starring the cast appeared; Kelley earned $1 million for the final film, Star Trek VI: The Undiscovered Country (1991).

Being identified so closely with one role left the series' cast with mixed emotions; Shatner called it "awesome and irksome". Koenig called it "bittersweet ... People are interested in Chekov, not me", but admitted that there was "a certain immortality in being associated with Star Trek". After Doohan complained about being typecast, his dentist replied "Jimmy, you're going to be Scotty long after you're dead. If I were you, I'd go with the flow". Doohan said "I took his advice, and since then everything's been just lovely", noting that being part of a "classic" was "beautiful. Your great-grandchildren will still be seeing Star Trek".

Some of the Next Generation actors also became typecast. Patrick Stewart recalled that a "distinguished Hollywood director I wanted to work for said to me 'Why would I want Captain Picard in my movie?' That was painful". His most prominent non-Star Trek film or television role, Professor X in the X-Men film series, shares similarities to Jean-Luc Picard. Stewart stated "I don't have a film career. I have a franchise career"; he continues to work on stage as a Shakespearean actor. The Next Generation had one of the largest budgets of its time, and the cast became very wealthy. Jonathan Frakes stated that "it's better to be type-cast than not to be cast at all." Michael Dorn said in 1991, "If what happened to the first cast is called being typecast, then I want to be typecast. Of course, they didn't get the jobs after 'Trek.' But they are making their sixth movie. Name me someone else in television who has made six movies!"

Other examples John Larroquette said that after winning four consecutive Emmy Awards, "it was 10 years after Night Court ended before I got a role as a dad. Because Dan Fielding was such a bizarre character, he had made such an impression, that typecasting does happen. Every role was some sleazy lawyer or some sleazy this or some sleazy that." During his years on the comedy Married... with Children, Ed O'Neill's scenes were cut from the film drama Flight of the Intruder (1991) after a test audience laughed when he was on the screen.

Jon Hamm stated that after the success of Mad Men, he received "about 40 scripts that were all set in the 60s, or had me playing advertising guys" like his character Don Draper.

Clayton Moore, who played the Lone Ranger in the Golden Age of Television, embraced his typecasting, stating that he had "fallen in love" with the character of Lone Ranger, and regularly appeared in public in character, to the point that Jack Wrather, who owned the character, issued a cease and desist order to Moore in 1979. The dispute was dropped in 1984 and Moore resumed his appearances. In a similar case, Alan Hale Jr. parlayed his fame as Skipper Jonas Grumby on Gilligan's Island into a seafood restaurant and a travel agency that offered three-hour boat tours.

Jonathan Frakes' sentiments about typecasting were echoed by Ben McKenzie, who became a star in the role of Ryan Atwood in The O.C. at age 24, after two years of seeking acting work in New York City and Los Angeles. Eleven years later, after starring in two more television series playing what The New York Times described as a "quiet, guarded leading man", McKenzie said that "if you are being stereotyped, that means you have something to stereotype. So they're casting you. That is an amazing thing. That is a gift. Worry about being pigeonholed in your 50s."

Daniel Radcliffe was cast as Harry Potter at age eleven, playing the character over ten years in an eight-film franchise. Afterwards, Radcliffe needed to handle the transitions out of being a child actor and to playing other roles. His career following the Harry Potter franchise has included appearing on stage, as in Martin McDonagh's The Cripple of Inishmaan; in independent films such as Kill Your Darlings, in which he played Allen Ginsberg; and major studio films such as Victor Frankenstein, in which he played the hunchback Igor, and romantic comedies such as The F Word (released in some countries as What If?).

Gary Sandy noted that being typecast as handsome characters such as Andy Travis on WKRP in Cincinnati strictly limited the amount of roles he was offered and the control he had over his choice of scripts; he left television after his role on that show, spending the rest of his career on stage.

Peter Robbins largely left acting after aging out of his most famous role, the voice of Charlie Brown. He retained a strong affection for the role throughout his life, including having a tattoo of the character.

Marilyn Monroe was typecast as a sex symbol of the 1950s throughout her acting career. Notable for portraying comedic "blonde bombshell" sex symbol characters in films such as Niagara (1953) and How to Marry a Millionaire (1953), as well as in musical comedies such as Gentlemen Prefer Blondes (1953), Monroe stated in late 1954 that she was "tired of the same old sex roles", and portrayed an embittered, pessimistic character for her final acting role in the black comedy film The Misfits (1961).

Historical-real characters Soviet actor Mikheil Gelovani depicted Joseph Stalin in 12 films made during the leader's lifetime, which reflected his cult of personality. Among them were The Great Dawn (1938), Lenin in 1918 (1939), The Vow (1946), The Fall of Berlin (1950) and The Unforgettable Year 1919 (1952). These films were either banned or had the scenes featuring Stalin removed after the 1956 Secret Speech. Following Stalin's death, Gelovani was denied new roles since he was so closely identified with Stalin. According to The Guinness Book of Movie Facts and Feats, Gelovani had probably portrayed the same historical figure more than any other actor.. Page 105. Die Zeit columnist Andreas Kilb wrote that he ended his life "a pitiful Kagemusha" of Stalin's image.

Vaughn Meader is another example, as he depicted President John F. Kennedy in the 1962 comedy record The First Family. Meader's career success came to an abrupt end after President Kennedy's assassination on November 22, 1963. Meader's TV and nightclub bookings were all canceled. His career never rebounded as he was too closely associated with President Kennedy and his attempts to criticize his typecasting also led to his indirect blacklisting.The Surprising Story of Famed JFK Impersonator Vaughn Meader (and Why You've Never Heard of Him) Mental Floss. Retrieved January 23, 2019.

Playing against type "Playing against type" is when an actor performs in a role or style different from the types of roles that they are known for.

Christian Bale's role as Patrick Bateman in American Psycho (2000) was different from his earlier performances and he was warned against the film. Similarly, when he was offered the role of Batman in Christopher Nolan's Batman Begins (2005), he was warned that he would be forever known as only Batman and would have trouble getting roles. The Dark Knight trilogy turned out to be a blockbuster and Bale's performance was appreciated. Bale has since performed in a range of award-winning roles. Jackie Chan was originally known for playing heroic and physically comedic roles in action and adventure films across over three decades. He was cast against type for a serious role as a Chinese immigrant opposite Pierce Brosnan as a corrupted Irish politician in the 2017 thriller The Foreigner, for which Chan garnered critical acclaim. Sacha Baron Cohen was known for his creation and portrayal of the fictional satirical characters Ali G, Borat Sagdiyev, Brüno Gehard, and Admiral General Haffaz Aladeen, before portraying Israeli spy Eli Cohen in the Netflix miniseries The Spy (2019). Bryan Cranston had played the immature, childish character Hal on Malcolm in the Middle. When Vince Gilligan approached AMC about his plan to cast Cranston as the morally dubious Walter White in Breaking Bad, the network was opposed to his casting in light of his previous comedic work. Tom Cruise was typically known for playing heroes before director Michael Mann cast him as an amoral hitman in Collateral (2004). Tony Curtis was known as "Hollywood's most handsome matinee idol"; as such, he was cast against type when he played serial killer Albert DeSalvo in The Boston Strangler (1968). Matt Damon was at first best known for his dramatic performance skills, as showcased in Good Will Hunting (1997), before being cast against type as the action hero Jason Bourne in the Bourne films. Henry Fonda, best known for playing morally upright, everyman heroes, was cast by director Sergio Leone to play a sadistic villain in the Western Once Upon a Time in the West (1968). Film critic Roger Ebert argued that much of the principal cast in Once Upon a Time in the West were cast against type: "Fonda is the bad guy for once in his career; Charles Bronson is impressively inscrutable as the mysterious good guy; and Jason Robards is a tough guy, believe it or not." Ice-T, who achieved fame as a gangsta rap artist early in his career, garnered critical acclaim for his subsequent acting roles as police detectives in New Jack City (1991) and Law & Order: Special Victims Unit.