Dunder Mifflin had many faithful employees in The Office, but who worked at the Scranton branch the longest? Throughout the course of The Office's nine-season run on NBC, viewers got a chance to meet many personalities working for Dunder Mifflin. Most of the show revolved around Michael Scott (Steve Carell), Jim Halpert (John Krasinski), Pam Beesley (Jenna Fischer), and Dwight Schrute (Rainn Wilson).
The Scranton branch of Dunder Mifflin included many other employees who appeared in nearly every episode. The sales department included Phyllis Lapin (Phyllis Smith) and Stanley Hudson (Leslie David Baker), while accounting included Angela Martin (Angela Kinsey), Oscar Martinez (Oscar Nunez), and Kevin Malon (Brian Baumgertner). Other employees at the Scranton branch include Creed Bratton, Toby Flenderson, Meredith Palmer, and Kelly Kapoor. And even though the group expands as the show goes on, this original collection of employees are the heart of The Office from the start.
Even though Michael is the Regional Manager of this branch, he isn't the one who has been there the longest. The Office repeatedly references Michael's younger days as a salesman, but he started at Dunder Mifflin in 1992, several years after graduating high school. Viewers don't get official hire dates for Phyllis or Stanley, but Michael does say that Phyllis is the "resident senior" at Dunder Mifflin Scranton during season 3. That term would seem to indicate that Phyllis is both the oldest person at the branch but also the one who has been there the longest. While audiences know that the age part isn't true, since she and Michael are the same age, this could just be another reference by Michael to Phyllis being the matronly figure of the office. But, The Office also reveals that Stanley was hired the day before Phyllis, so Michael's entire statement is not accurate.
Even without exact hire dates for Phyllis and Stanley, it is clear that Michael never held this record. Phyllis and Michael are the same age, but Michael didn't start there until he was 27. Michael thinks of Phyllis being older and more experienced than him, though, which could signal she was there before him. Plus, Michael left Dunder Mifflin in season 7, which gave Phyllis and Stanley two more years to work there. Meanwhile, a single day could be what separated Stanley and Phyllis at first. There's also potential evidence that Creed is actually the longest-tenured Dunder Mifflin employee. In season 7, Jo Bennett says that the person who has been at the Scranton Branch the longest should become the new Regional Manager. Despite not knowing when Creed was hired - or if he ever really was - the search committee makes Creed the new manager to fulfill Jo's request.
With some conflicting points about who has been at Dunder Mifflin the longest throughout The Office's run, everything is made clear by the very end. Season 9's finale revealed that Stanley finally retired after the Dunder Mifflin documentary aired. It is also revealed that Creed is a criminal and faked his own death to avoid being arrested, but he is detained by the end of the finale. Due to these events, Phyllis became the longest-tenured employee of Dunder Mifflin Scranton. She presumably has years of experience separating her from any of her coworkers too. But, she also doesn't appear interested in retiring any time soon as she wants to fatten up Stanley's replacement to make him more like her old work friend. Unless The Office reunion happens with the original cast in the future and clears up what happened next, Phyllis should go down as Dunder Mifflin Scranton's longest-lasting employee. That is until Dwight inevitably takes the crown since he'll never leave the company.