The Marvel Cinematic Universe may not recognize all television series that came out of Marvel Entertainment as canon, but plenty of cameos and crossovers therein suggest otherwise. The series that were produced by Marvel Entertainment were not crafted by Kevin Feige and the other executives behind MCU films but have still managed to garner major followings for themselves despite their comparatively limited connection to the larger franchise. Even so, after years of claiming that these shows were not canon, the MCU has recently reversed its position on certain projects by including cameo appearances from characters who had previously appeared in Marvel Entertainment series, adding to a growing list of crossovers.
The MCU's first television series came in the form of Agents of SHIELD, which directly followed the events of The Avengers. In its celebrated seven-season run, Agents of SHIELD expanded the MCU in new and exciting ways, paving the way for many more series to follow in its footsteps. However, after Kevin Feige was placed in full creative control of Marvel, the company began dialing back its expanded series in favor of Disney+ ventures that would directly tie into the events of the larger franchise. Every show predating WandaVision seemed lost until recent appearances in Hawkeye and Spider-Man: No Way Home suggested otherwise.
Clark Gregg
Clark Gregg is well-known in the Marvel fandom for portraying SHIELD agent Phil Coulson throughout the first phase of the MCU but became even more beloved for leading one of the MCU's best shows, Agents of SHIELD. Despite his death during the events of The Avengers, Coulson was resurrected in his spinoff series, surviving for several years after being stabbed through the heart by Loki. Coulson went on to appear in Captain Marvel, becoming the only regular cast member from Agents of SHIELD to appear in an MCU film after his show began airing. While Gregg's Captain Marvel appearance seemed promising, he has made no subsequent appearances in MCU films.
Cobie Smulders
Cobie Smulders's SHIELD agent has made frequent appearances in the Marvel Cinematic Universe since her debut in The Avengers, including in the franchise's exciting Disney+ venture, Secret Invasion, which may finally honor Maria Hill as the compelling character she is. Hill may be best known for showing up in major crossover films, but she made one of her earliest appearances in the pilot for Agents of SHIELD, becoming one of the few MCU characters aware of Coulson's resurrection. Smulders returned as Maria Hill twice more during the show's run, acting as an important connection to MCU projects like Captain America: The Winter Soldier and Avengers: Age of Ultron.
Jaimie Alexander
Jaimie Alexander made her MCU debut as the fearsome Asgardian warrior Lady Sif early in Phase 1, during 2011's Thor. Since her initial live-action appearance, Sif has rarely appeared in the MCU, though she did make multiple appearances in episodes of Agents of SHIELD. She first appeared in season one, enlisting the help of Coulson's team to track down an escaped Asgardian prisoner known as Lorelai. She would later appear in season two after losing her memory during a fierce battle. This marked the last time that Sif would appear for many years, as the character sat out Thor: Ragnarok before finally returning in Loki and Thor: Love and Thunder.
Maximiliano Hernandez
Maximiliano Hernandez portrays SHIELD agent Jasper Sitwell in the MCU. After appearing sporadically in the MCU, Sitwell played a major part in Agents of SHIELD's improvement of the Hydra twist in The Winter Soldier. Sitwell appeared on several occasions throughout season one of Agents of SHIELD, gradually teasing the reveal that SHIELD had been infiltrated by Hydra. Hernandez's television appearances eventually led directly into the events of The Winter Soldier, wherein Sitwell became one of the first Hydra operatives uncovered by Captain America before being killed by a brainwashed Bucky Barnes. Adam Faison later portrayed a young Sitwell during a series of flashback sequences in Agents of SHIELD's fifth season.
Samuel L. Jackson
By far the biggest Marvel character to be featured in a crossover with Agents of SHIELD was Director Nick Fury. After Iron Man, Nick Fury defined the MCU's first phase, bringing the Avengers together for the first time. However, he also continued to serve as the operating director of SHIELD while managing Earth's Mightiest Heroes. This side of Fury's career is explored deeper in Agents of SHIELD. Though the character is usually referred to rather than seen, Samuel L. Jackson does appear in multiple episodes of the show's first season, including the finale in which Fury makes Coulson his successor as SHIELD director following the events of The Winter Soldier.
Henry Goodman
Although its receptions seemed to imply that the second Avengers film wasn't quite as groundbreaking as its predecessor, Age of Ultron did one thing better than the original Avengers by tying in its events to Marvel's outlying series. Agents of SHIELD included plenty of set-up for Age of Ultron, including in the form of Henry Goodman's Dr. List, a close associate of Baron Struker. After appearing in The Winter Soldier's mid-credits scene, List was featured heavily in the second season of Agents of SHIELD, setting up his involvement in the Avengers film, where he was presumably arrested by Earth's Mightiest Heroes, never to be seen in the MCU again.
Powers Booth
Powers Booth portrayed Gideon Malick, who was eventually revealed to be a chief figure behind Hydra's unprecedented rise to power in the MCU. Malick made a brief appearance in The Avengers as a member of the World Security Council behind SHIELD and Nick Fury. Season three of Agents of SHIELD revealed that he had been part of Hydra's infiltration of SHIELD from the very beginning and had even become Hydra's leader in the time since their plot was hatched. Malick sought to resurrect the Inhuman god Hive and was successful, though his plan ultimately backfired, resulting in him and his entire family being killed, wiping out all the Malicks forever.
William Sadler
William Sadler plays a small but important role in the MCU. Although the infamous Mandarin twist is Iron Man 3's biggest moment, the film also introduced the Avengers' relationship with the United States itself through the inclusion of Sadler's President Matthew Ellis. President Ellis also made three appearances in Agents of SHIELD, revealing that he was aware of the organization's secret continuing operations after the events of The Winter Soldier. While Ellis's term as President in the MCU has long since ended, the franchise will finally be revisiting its connection to United States government officials during the events of Secret Invasion, which will introduce Dermot Mulroney's new character, President Ritson.
Hayley Atwell
After appearing in Captain America: The First Avenger, Peggy Carter became a fan-favorite character, leading to recent petitions for Agent Carter to get her own MCU film. While this may or may not ever come to fruition, Atwell's character does already have her own spinoff in the form of Agent Carter, a series that ran for two seasons on ABC. In addition to minor appearances on Agents of SHIELD, Peggy's story was widely fleshed out during her series, leading to the character's cameos in later MCU films like Avengers: Endgame. The Multiverse has also introduced the superhero Captain Carter, a variant who may still have a future in the MCU.
Neal McDonough
Neal McDonough first portrayed one of the Howling Commandos in Captain America: The First Avenger. Since then, McDonough has appeared as Dum-Dum Dugan on several occasions, including several episodes of Agents of SHIELD and Captain Carter. While McDonough was never promoted to a main cast member in either of these shows, both SHIELD-centered series made it a point to address Dum-Dum Dugan's continued adventures after the disappearance of Captain America. Furthermore, The Winter Soldier confirms that Dugan, like the other of the Howling Commandos, survived the end of World War II, though he likely ed away at some point prior to the discovery of the frozen Steve Rogers.
