Anna Faris left Mom after Season 7 mainly because she wanted to step away and open up space for new opportunities and a different phase of her life and career, rather than because of any confirmed on‑set feud or scandal.

What Anna Faris has said

  • In her official exit statement in 2020, Faris called her seven years on Mom “fulfilling and rewarding” and said her “journey as Christy has come to an end, allowing me to pursue new opportunities.”
  • In later interviews, she described the move more like a sabbatical from acting, saying it wasn’t a sharply planned career play so much as stepping back from a long‑running commitment.

Behind‑the‑scenes context

  • Faris left even though she had reportedly signed a two‑year contract that could have kept her on the show through Season 8, which is why fans and even people in the industry saw the exit as sudden.
  • The production had to quickly retool Season 8 around Allison Janney and the remaining ensemble, and Christy’s in‑show explanation was that she left for Georgetown University, giving the character an off‑screen happy progression rather than a dramatic send‑off.

Speculation and fan/forum chatter

  • Entertainment commentary and fan forums often speculate about additional factors such as creative dissatisfaction (Christy feeling “stuck” or underwritten in later seasons), long‑term burnout on a network sitcom, or wanting more control through projects like her Unqualified podcast, but these angles are not confirmed by Faris herself.
  • Some gossip pieces have floated rumors of jealousy or tension because Allison Janney’s performance drew more awards attention, but cast members have publicly spoken supportively of Faris, and no concrete evidence has surfaced that a feud was the real driver.

What she did after leaving Mom

  • After leaving, Faris leaned further into projects outside the traditional multi‑camera sitcom grind, including focusing on her Unqualified podcast and being choosier about on‑screen work, which fits the picture of someone deliberately reshaping a long‑term career rather than chasing one specific “bigger” job.
  • She has also talked about reassessing her work–life balance and even briefly considering stepping away from Hollywood more broadly, reinforcing that her Mom departure was tied to a broader life and career recalibration.

TL;DR: Why did Anna Faris leave Mom?
Because after seven seasons she chose to end her run as Christy early so she could step back, rebalance her life, and leave room for new or different opportunities, while rumors about feuds or drama remain unproven and mostly in the realm of gossip.

Information gathered from public forums or data available on the internet and portrayed here.