Tammy is conniving and ruthless, taking advantage of Ron to get Lot 48 and doing anything to see him miserable. She is also very sexual, and Leslie claims Tammy is a masterful seducer, due to the fact that in "Ron & Tammy: Part 2", Tammy flashed a whale tail thong, and then began slapping a stick of beef jerky against her face and chest, something that would normally ensnare Ron. When she and Ron first got together, Ron's first wife Tammy 1 threw acid on her foot.
Tammy first appears in "Ron and Tammy", when she lays claims to Lot 48 in order to expand the library to another branch. Leslie confronts Tammy on this, but Tammy persuades Leslie that Ron is exaggerating her negative qualities. Ron says various things about her, including that looking into her eyes is like looking into "the eye of Satan's butthole" and that she is "a machine created to destroy human happiness". Leslie then brings Tammy to the offices to talk with Ron. Ron and Tammy go to get a cup of coffee at Frank's Restaurant to sort out their differences, but it is not successful. It starts with Ron insulting Tammy, then progressing to a shouting match, and then the two eat breakfast at separate booths. Next, the two are seen kissing over the booths, and they begin to have sex on the table, leading to Ron breaking the table during this. The couple is asked to leave, where they go to their "usual spot", the Motel Glen Capri, and Ron's pants can be seen falling and Tammy shirtless as they enter their room. Ron is powerless to Tammy's sexuality, and he gives Tammy the lot in exchange for sex. Leslie helps Ron to confront Tammy, which he successfully does, regaining control of the lot, but leaving with a pushpin in his forehead and part of his mustache missing.
Tammy again appears is "Ron & Tammy: Part 2". Tom Haverford is jealous of seeing Ron date his ex-wife, Wendy Haverford, so he brings Tammy, who thinks his name is Glen, as his date to the party thrown by Leslie for the police so they will act as security for the Harvest Festival. Tammy acts very sexually during the party, leading Ron to ask her to stop for Tom's sake. Tammy yells, and the police descend. The two once again decide to get a cup of coffee and sort out their differences. Ron again is ensnared by Tammy, first yelling at her, then kissing her on a police car, getting his hair braided, creating a wedding registry, re-marrying Tammy and having sex in the courthouse, leading to their arrest. Tammy is later confronted by Tom, and she assaults him, slapping him, throwing him into a bookcase, and cackling at his pain. Ron is freed from Tammy's charm after he sees her ugly side again.
In "Ron and Tammys", Ron has once again fallen for a Tammy, but this time it's the first Tammy 1. Leslie goes to Tammy to ask her for help getting rid of the first Tammy, as she's turned Ron into a wimp. Leslie explains that "to beat Godzilla, we need Mothra". However, even Tammy 2 is scared of Tammy 1, explaining that Tammy 1 threw acid on her foot when she first found out about her and Ron's relationship.
In "The Trial of Leslie Knope", Chris Traeger calls Tammy in as his "killer witness" in Leslie's ethics trial. Tammy claims she has evidence linking Ben Wyatt and Leslie to lawbreaking. She begins to say she has several photographs that will definitively link them to the crimes, but when Chris reminds her she's under oath, she says they will prove nothing. She then gets up and rushes out, wishing Leslie good luck as she walks past her.
In "Ron and Diane", Tammy shows up unannounced to Ron's award ceremony at the Indiana Fine Woodworking Association, seeking to sabotage his blooming relationship with Diane Lewis. She makes a number of attempts at seducing Ron despite Leslie's great efforts to keep them apart; despite her determination, Diane is not at all threatened by Tammy, but more by Leslie due to the strong friendship she and Ron share. Later, Tammy waits in Ron's car, hoping to seduce him, but Leslie ends up hijacking the vehicle and driving them both out to the middle of nowhere. She and Tammy fight for the keys in a dumpster, then drive back to the now vacant award ceremony. Enraged, Tammy arms herself with a hatchet and chases Leslie throughout the night. The next morning, Tammy has been arrested by the police. She tries once more to seduce Ron when the police return his car to him, but she is swiftly put in her place by Diane. When an exhausted Leslie is found stuffed inside the trunk, Tammy laughs in amusement.
Tammy briefly appears at the Pawnee-Eagleton Unity Concert in "Moving Up" to once again try and tempt Ron. Her ineffectiveness at seducing him reaffirms to Ron his commitment to his family, and he decides to appear as Duke Silver to play in the final song of the Unity Concert.
In "Ron & Jammy," Tammy has gotten her hooks into Jeremy Jamm and has turned him into a facsimile of Ron, only allowing him to eat steak and drink whiskey, even though he has irritable bowel syndrome. This ends up forcing another confrontation with Ron, as Jamm is the key deciding vote on whether to re-zone the Newport land for commercial use, and Leslie and Ron are on opposing sides of the issue. However, when they see how miserable Jamm is under Tammy's thumb, they temporarily put aside their differences to help shake him from her grasp, training him with Ron's "Tammy deprogramming" exercises to desensitize him from Tammy. Later that day, Jamm confronts Tammy at the Pawnee Library and successfully breaks up with her, even resisting the urge to have sex with her after Tammy gets naked in front of the trio.
- Ron and Tammy
- Ron and Tammy: Part II
- Li'l Sebastian
- Ron and Tammys
- The Trial of Leslie Knope
- Ron and Diane
- Moving Up (Part 1)
- Moving Up (Part 2)
- Ron & Jammy
- The actress who portrays Tammy 2, Megan Mullally, is married to Nick Offerman, who portrays Ron Swanson.
- In Ron and Jammy, Ron states that Tammy once hid in his attic for 6 days, waiting for him to return home. She survived by drinking rain water and eating rats.
- According to her library card, her full name is Tammy Swanson Swanson. This is because Tammy and Ron married twice.
- On her shelf she has a book titled "Sperm Suicide".