Aside from being Ryan's older sister, she is a highly stressed OB/GYN, who attempted to get Ryan a job alongside her, which failed. She is very bossy and snappy, seeing as she has to work crazy hours and deal with her kid brother, whom seems to be her typical verbal punching bag. She, like others, does not see Wilfred the way Ryan does, and, in one episode (Anger), she discards Wilfred's gift (A dead rat), nearly gets electrocuted by said dog (She would have if Ryan hadn't saved her and her boss), and got wine spilled all over her. She is also guilty of accidentally letting Ryan's pet Jack Russell Terrier "Sneakers" drown in the pool when they were kids. She is currently pregnant with Arturo's child by cheating on her husband. She previously left for India and now is back, having forgiven Ryan after everything. She later gives birth to a son, Joffrey.
Kristen was born to Henry and Katherine Newman, but when the two had a falling out, Catherine joined a cult and slept with the leader which gave Kristen her half-brother Ryan. Ryan was welcomed into Henry's life and grew up with Kristen and his mother too. As a girl, Kristen's relationship with her mother was strained as one time on a vacation she said she could be president of the "Itty Bitty Titty Commity". According to Catherine, Kristen had an attracting to African American men growing up. Kristen often acted as a third parent to Ryan throughout their life and consoled his behavior around Henry and Catherine. She married a man naed Leo in her adulthood but their relationship became strained over the years.