The rest of actors that portray the other characters began either being credited as a co-star or guest star and eventually became credited as starring after the opening credits in alphabetical order, with the exception of Melora Hardin, David Denman, Catherine Tate and Ed Helms, who, when credited, always appeared first (in that order) before the other actors, and Amy Ryan, who, upon joining the cast, appeared last receiving the "and" credit.
In the episodes in which Melora Hardin and Amy Ryan were not credited as regular cast members, they were credited as "Special Guest Stars", after the starring cast (in the seventh and fifth seasons respectively). Idris Elba, Kathy Bates and Will Ferrell also received this credit for their appearances.
Beginning with the second-season episode "Boys and Girls", Melora Hardin and David Denman are credited as starring. The two are only credited in the episodes they appeared in. After season 3, Denman is no longer credited as starring. After season 5, Hardin is no longer credited as starring.
Beginning with the seventh-season premiere "Nepotism", Zach Woods is credited as starring.
Beginning with the seventh-season episode "Sex Ed", Amy Ryan is credited as starring, under an "and" title. She did not appear in the six episodes that followed, but resumed her starring status in the seventh-season episode "Classy Christmas".
Beginning with the ninth-season premiere "New Guys", Clark Duke and Jake Lacy are credited as starring; B. J. Novak and James Spader are removed from the opening credits; and Mindy Kaling and Zach Woods are longer credited as starring.
Despite her status as a guest star, Rashida Jones appears on the DVD cover for the third season, making her the only member of the recurring cast to ever appear on a DVD cover.
Despite being billed as a recurring role for much of season 3 and promoted to an opening credit starring role in season 6, Ed Helms has appeared on 4 of the 7 DVD covers (3, 5, 6, 7). Meanwhile, Craig Robinson replaced B. J. Novak on the season 7 DVD cover, making it the first season Novak has not appeared on the DVD cover.
Several of the cast members are from Massachusetts: Carell is from Acton; Kaling is from Cambridge and former high school classmates Krasinski and Novak are from Newton. James Spader, who joined the main cast in season 8 as Robert California, is from Boston.