On September 24, 2013, the Marvel Cinematic Universe took its next big step when the first-ever MCU television series premiered on ABC. Agents of SHIELD was an instant draw because it saw the return of Agent Phil Coulson (Clark Gregg), who had died in The Avengers just one year earlier. As the show approaches its seventh and final season, debates continue to rage on about whether or not the series is MCU canon. While an argument can be made that the show's sixth season doesn't properly tie in with the Marvel movies (more on that later), there's absolutely no denying that most of the series is bonafide MCU canon. People are still taking to Reddit to debate the series' stance in the MCU, but the show has proved time and time again that it fits in with the movies.
The cast of Agents of SHIELD have often shared the story about learning their show's fate through a screening of Captain America: The Winter Soldier. Once it was revealed that Hyrda had been infiltrating SHIELD for years, the stars of the series wondered what that meant for their show, which was only in the first season at the time. Not only did AoS tie in with The Winter Soldier beautifully, but it's arguably when the show finally found its footing. (Although, for the record, some of us didn't need 17 episodes to be convinced. I personally knew the show was for me with the back-to-back episodes "FZZT" and "The Hub," which occurred much earlier in the first season). Not only did this massive twist reset the MCU, but it solidified AoS's place in the canon. We got to see SHIELD's fall happen from perspectives other than Cap's, and watch as some of the show's main characters were revealed to be Hydra (RIP Ward).
While the Winter Soldier tie-in was the biggest MCU connection, it certainly wasn't the only thing that connected the show with the movies. Samuel L. Jackson guest-starred as Nick Fury, Maximiliano Hernández appeared as Jasper Sitwell, Jaimie Alexander showed up as Lady Sif, and Cobie Smulders reprised her role as Maria Hill. Hayley Atwell also appeared in flashbacks as Peggy Carter, and she won't be the last Agent Carter star to cameo on the series. Also, we can't forget that Stan Lee appeared in Agents of SHIELD's 13th episode, cementing its Marvel credibility.
The show also tied in with Thor: The Dark World, Avengers: Age of Ultron, and made plenty of other small references to the films. Of course, as Agents of SHIELD progressed, it was able to stand on its own with fewer tie-ins and movie callbacks, but that doesn't mean it wasn't always in line with the films. That is, until the end of the show's fifth season.
The canon argument came back in full force when SHIELD briefly mentioned Thanos' attack towards the end of season five. The finale aired around the same time Avengers: Infinity War was released in theaters, but the show was put in a unique situation. At the time, it was unclear if the series would be renewed, which meant the season five finale was filmed as a potential series finale. While it was surprising not to see anyone get dusted on AoS after Infinity War, it also would've been an epic downer if the show ended for good in the middle of Thanos' decimation. The choice to mention what was happening in the movies while also glossing over Thanos' big finish felt like the best they could do at the time.
Season six of SHIELD takes place a year after the season five finale, which means it technically occurs during the five-year time jump mentioned in Avengers: Endgame. Since SHIELD makes no mention of The Snap, it's understandable that people would argue the series is no longer canon. However, Agents of SHIELD spent so long working hard to tie-in with the MCU, it'd be unfair to discount all of the work put into the "it's all connected" mindset. It's hard to believe they would throw away everything they did to keep the stories together, which is why we're choosing to believe SHIELD's last season took place in a potential alternate timeline created by Cap when he returned the Infinity Stones in Avengers: Endgame. Now that the seventh season will see the agents doing a bit of time-traveling of their own, who knows what present-day they'll return to. No matter what the final season has in store, Agents of SHIELD has proven itself worthy of the Marvel Cinematic Universe time and time again, and deserves to be treated as canon.
Agents of SHIELD returns on May 27th.