The Definitive Timeline: What Season Does Addison Leave Grey's Anatomy (And All Her Shocking Returns)

Dr. Addison Forbes Montgomery, the neonatal surgeon who burst onto the scene in the *Grey's Anatomy* Season 1 finale, immediately became one of the most iconic and complex characters in Shondaland. Her unforgettable entrance—"You must be the one screwing my husband"—set the stage for a dramatic run on the show. As of today, December 13, 2025, fans are still tracking her journey, especially following the recent, exciting news of her continued involvement in the flagship series.

The short, definitive answer to "what season does Addison leave *Grey's Anatomy*?" is Season 3. However, the story of Kate Walsh's character is far more complicated than a simple exit, involving a successful spin-off, multiple crossover events, and a series of high-stakes guest appearances that continue into the most current seasons.

The Original Exit: The Exact Episode Addison Left as a Series Regular

Addison Montgomery's initial departure from *Grey's Anatomy* was not a tragic death or a sudden firing, but a strategic move by the network to launch a new series. Her final episode as a main cast member was the dramatic Season 3 finale.

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• Season of Departure: Season 3
• Episode of Departure: Episode 25, "Didn't We Almost Have It All?"
• The Context: The two-part episode preceding the finale, "The Other Side of This Life" (Episodes 22 and 23), served as a "backdoor pilot" for her spin-off show, *Private Practice*.

In this pivotal two-part story, Addison travels to Santa Monica, California, to visit her old friends from medical school, Naomi Bennett and Sam Bennett, at their private practice, the Oceanside Wellness Group. The trip was a temporary escape from the intense love triangle drama with her estranged husband, Derek Shepherd (McDreamy), and his new love interest, Meredith Grey, as well as her own brief fling with Mark Sloan (McSteamy). The Season 3 finale then confirmed her choice to leave Seattle Grace Hospital (the original name of the hospital) to start a new life and career in Los Angeles, officially concluding her run as a series regular on *Grey's Anatomy*.

The Private Practice Years: Addison’s Six-Season Journey in Los Angeles

Addison's departure was not the end of her story; it was a new beginning. The spin-off, *Private Practice*, followed her as she joined the Oceanside Wellness Group, a cooperative medical practice focused on a more holistic approach to patient care. This move allowed the character to grow beyond the confines of the love triangle and explore her own personal and professional life in depth.

• Spin-off Series: *Private Practice*
• Series Run: Six seasons, from September 26, 2007, to 2013
• Key Character Development: Over the course of the spin-off, Addison navigated a new set of complex relationships with characters like Pete Wilder, Sheldon Wallace, and eventually found lasting love and adopted a son, Henry, with Jake Reilly. She also worked closely with her former sister-in-law, Amelia Shepherd (Derek’s sister), who later made her own transition to *Grey's Anatomy*.

The success of the spin-off solidified Addison's status as a fan-favorite character created by Shonda Rhimes. Even while starring on *Private Practice*, Kate Walsh occasionally returned to *Grey's Anatomy* for major crossover events, proving that her connection to the original show and its characters, like Dr. Webber and Callie Torres, was never truly severed.

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The Shocking Returns: Addison’s Resurgence in Recent Seasons

Even after *Private Practice* concluded, the door to Grey Sloan Memorial Hospital (the hospital's later name) remained open for Addison. Her sporadic appearances in later seasons have been a massive draw for viewers, injecting nostalgia and high-stakes drama back into the show. These returns are crucial for understanding her full timeline on *Grey's Anatomy*.

The Early Guest Spots (Seasons 4–8)

Following her move, Addison returned for several memorable guest spots, often for complex surgical cases or important character milestones. She was credited as a "Special Guest Star" during this period. Her appearances included Season 4, Episode 13, and the two-part crossover event in Season 5, Episodes 15 and 16, which often involved major surgeries or personal support for the Seattle doctors.

The Emotional Comebacks (Seasons 18 & 19)

After a long absence, Kate Walsh returned to *Grey's Anatomy* as a recurring guest star in Season 18 and Season 19, much to the delight of longtime fans.

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• Season 18: Her return in Season 18 was deeply emotional, featuring a powerful reunion with Meredith Grey and a poignant moment in the hospital's new teaching program.
• Season 19: Her role became even more significant in Season 19, particularly in Episode 11. This storyline saw her travel across the country to provide essential Reproductive Healthcare services, a timely and sensitive plot that reflected real-world issues. During this episode, she and a pregnant resident were attacked by anti-abortion protestors, a shocking and intense moment that left fans wondering if the character would be killed off [cite: 9 (from step 1), 12 (from step 1)].

The Latest News: The Confirmed Season 22 Return

In the most recent and exciting update, Dr. Addison Montgomery is confirmed to return for *Grey's Anatomy* Season 22.

• Season 22: Kate Walsh is set to reprise her role as a Special Guest Star in the upcoming second half of the season.

This news confirms that while Addison left as a series regular at the end of Season 3, her character remains deeply interwoven with the fabric of the *Grey's Anatomy* universe. From the love triangle with Derek and Meredith to her own successful career and personal life in *Private Practice*, and now her crucial work in the modern era of Grey Sloan, Addison Montgomery’s journey is one of the longest and most beloved in the show's history.