Television writers have the difficult task of creating small roles that help further the plot on a short-term basis without overshadowing the main characters or becoming too ingrained in the overarching storyline. Although most of these characters come and go as intended, often for less than three episodes, others show so much promise that the writers can't help but include them in more episodes.
Whether the actor displayed immediate chemistry opposite the lead, as was the case with Luke Kirby in The Marvelous Mrs. Maisel, or the character resonated so strongly with audiences that they demanded more, such as James Marsters' portrayal of Spike in Buffy the Vampire Slayer, the performances by these actors turned their guest roles into important recurring characters or even series regulars.
Jessica Capshaw
Grey's Anatomy
Grey's Anatomy is no stranger to the character turnover that comes with such a long-running show. As a medical drama, the program is consistently introducing patients that succumb to their illnesses or are healed and released as well as doctors that move on to other hospitals, never to be seen again. Jessica Capshaw's character, Arizona Robbins, was initially written for a three-episode arc, but her infectious smile and unique way of relating to her pediatric patients made her a fan favorite among Grey's Anatomy viewers.
It's hard to believe that Arizona was never meant to mentor Alex Karev as a pediatric surgeon, survive the infamous plane crash, or start a family with Callie Torres. Capshaw continued to portray Dr. Robbins from season five until her exit from the show in season fourteen.
Chris Pratt
Parks and Recreation
The iconic character, Andy Dwyer, was never meant to exist outside of being Anne's boyfriend in Parks and Recreation. Actor Chris Pratt was originally signed on for six episodes in season one, during which he would act as the catalyst for Anne Perkin's friendship with Leslie Knope and, of course, bring attention to the infamous pit.
Pratt's portrayal of the lovable and often dim-witted musician instantly endeared viewers as well as the producers to the character and by the end of season one, he was promoted to main character. Pratt's extended role in the show allowed the character to evolve while also launching his film career and eventual stardom with Guardians of The Galaxy and Jurassic World.
Luke Kirby
The Marvelous Mrs. Maisel
Luke Kirby's portrayal of the legendary real-life comedian, Lenny Bruce, was only intended to feature in the pilot of The Marvelous Mrs. Maisel. In a 2019 interview with Vanity Fair, creator Amy Sherman-Palladino discussed Kirby's captivating depiction of the comedian and the instant chemistry he shared with lead actress Rachel Brosnahan.
Kirby's way of looking at Brosnahan in their scenes threads the line between admiration and flirtation, building the perfect amount of tension and never coming across as predatory or manipulative. The recurring appearance of the character throughout the series allows Lenny to act as a sort of mentor and confidant for Midge as she rises through the ranks of the comedy world.
Noel Fisher
Shameless
Noel Fisher joined Shameless as the crass South Side thug, Mickey Milkovich. The infamous neighborhood bully was only scheduled for three episodes but Fisher's performance and masterful timing convinced showrunner John Wells to write a more extensive plot for Mickey. Due to Fisher's schedule, he was often billed as a guest star despite starring in more episodes than many other recurring characters.
Mickey Milkovich quickly became a favorite among fans of the show, known for his quotable one-liners and groundbreaking relationship with main character, Ian Gallagher. Ratings and audience opinion began to suffer when Fisher left the show after season five but his return in the season nine finale rekindled interest for the pair and allowed Mickey and Ian to develop into the best couple in Shameless.
Jane Widdop
Yellowjackets
Actor Jane Widdop's character, Laura Lee, was an integral part in Lottie's rise to power during season one of Yellowjackets, but the religiously motivated teammate was originally never supposed to make it off the plane. The writers had planned for Laura Lee to die among her unlucky fellow soccer players in the pilot episode but were so impressed during the table read, that they wrote more for Laura Lee's character.
Although at first glance, Laura Lee comes across as a prudish character who would cause trouble for others, Widdop's performance turned a classic trope into a complex character with surprising bravery. Jane Widdop turned their two-episode guest spot into an eight-episode character arc.
Bella Ramsay
Game of Thrones
Bella Ramsey stunned Game of Thrones viewers with her powerful performance as the young leader of Bear Island, Lyanna Mormont. Though the character was only supposed to appear in one scene, the showrunners knew immediately that Lyanna's story needed to expand past her singular introduction.
Lyanna Mormont became an instant hit with viewers who wanted to see more of the little girl who managed to successfully gain the respect of an entire nation. Later in the series Lyanna assists the Starks in electing Jon Snow and devotes her men to fight in the Battle of Winterfell. The decision to fight alongside her men and give her life for the sake of her people proves her legitimacy as a leader.
Aaron Paul
Breaking Bad
Breaking Bad showed one of the greatest dramatic duos with characters Walter White and Jesse Pinkman, but that dynamic was almost nonexistent. Creator Vince Gilligan planned for Aaron Paul's character, Jesse, to die by the end of the first season, acting as a source of guilt for Walt's character while also showing the audience that any character could be expendable.
By the time they were filming episode two, Gilligan had changed his mind and decided that Jesse was an essential part of the story. Aaron Paul's unique delivery of Jesse's lines helped shape the character into a complex symbol of the duality of man. Jesse allows the audience to more clearly see how lost Walt becomes in his pursuit of power.
Misha Collins
Supernatural
Castiel of Supernatural is another example of a character whose three-episode arc was turned into a main character role with the help of fans. Misha Collins never thought he would become a permanent part of the Supernatural cast but viewers loved the natural humor between Castiel and Dean and wanted to see more.
Creator Erik Kripke indulged the demand and began creating plotlines that would explore Castiel's dedication to good over evil and his struggle to adapt to life on Earth. Castiel provided plenty of comic relief through his attempts to pass for a human and captured the hearts of viewers as he became part of Sam and Dean's family over the course of 12 years.
James Marsters
Buffy the Vampire Slayer
James Marsters' guest spot on Buffy the Vampire Slayer as Spike turned into a series-long character arc, much to the dismay of creator Joss Whedon who took issue with viewers' affection for the monstrous vampire. After terrorizing Sunnydale High School during Buffy's parent-teacher conference, Spike's plan to kill citizens to heal his beloved Drusilla is revealed and the lovers become the "Big Bad" of season two.
Spike's frequent return to Sunnydale provides much-needed humor and the grudge between himself and Buffy creates the perfect amount of tension. The gradual character development of Spike from the villain into the ultimate anti-hero remains one of the most impressive feats of Buffy.
Estelle Getty
Golden Girls
Few shows are as memorable or easily recognized as The Golden Girls but many would be surprised to find out that Estelle Getty was not originally cast as a main character. The initial setup can be seen in the pilot episode with Charles Levin playing the fourth character, Coco, the wise-cracking butler for Dorothy, Blanche and Rose.
Getty's character, Sophia Petrillo, was only intended to guest star in the occasional episode but her chemistry with the other three women was too strong to ignore. Sophia replaced Coco as the fourth main character and was given all of his comedic insults. The resulting dynamic of an all-female-led cast is what made The Golden Girls such a success.