Preston Burke: Season 1-Season 3

Played by Isaiah Washington

Former head of Cardiothoracic Surgery at Seattle Grace

Was engaged to Christina Yang

Quit after leaving his fiancée before their wedding

Isobel Stevens: Season 1-Season 6

Played by Katherine Heigl

Surgical resident at Seattle Grace Hospital.

Fell in love with patient Denny Duquette & cut his LVAD wires in an attempt to save his life.

Diagnosed with Stage IV metastatic melanoma with metastasizes to the liver, brain, and skin in Season

Married Alex Karev in Season 5

Fired due to necessary cutbacks in Season 6 and left the show

George O’Malley: Season 1-Season 6

Played by T.R. Knight

Failed his intern exam and had to repeat his intern year

Married Callie Torres in Season 3 but cheated on her with Izzie Stevens

Died is surgery after jumping in front of a bus to save a woman’s life

Addison Montogomery-Shepherd Season 1-Season 8

Played by Kate Walsh

First appearance was in the Season 1 Finale

Married Derek Shepherd in New York but cheated on him with Mark Sloan

Followed Derek to Seattle where she convinced him to dump Meredith and give their marriage another try

Divorced Derek in Season 3

Regarded to be the best at neonatal surgery in the country

Denny Duquette: Season 2-Season 3, Season 5

Played by Jeffrey Dean Morgan

Heart patient suffering from Congestive Heart Failure at Seattle Grace

Love interest for his doctor Izzie Stevens

Died in the Season 2 finale due to a stroke after complications of his LVAD wires being cut

Appeared to Meredith as a ghost in Season 3 after Meredith drowned

Appeared to Izzie as a ghost in Season 5 to help her figure out she had cancer

Erica Hahn: Season 2-Season 5

Played by Brooke Smith

First appeared as a Cardiothoracic Surgeon at Seattle Presbyterian Hospital

Rival with surgeon Preston Burke

Came to Seattle Grace and a Cardiothoracic Surgeon in Season 4

Briefly dated Callie Torres

Leaves Seattle Grace after discovering Izzie Stevens purposely cut Denny Duquette’s LVAD wires and was not properly punished

Mark Sloan: Season 2-Season 9

Played by Eric Dane

Slept with Derek’s wife Addison in New York

Came to Seattle and reconciled with Derek in Season 2

Attending in Plastic Surgery

Had an on and off relationship with Lexie Grey throughout all seasons

Was in a plane crash in Season 8 that ultimately took his life in the Season 9 premiere

Admitted his love for Lexie in the Season 8 finale, minutes before she died

Has a daughter with Callie Torres and Arizona Robbins (Sofia)

Had the hospital named after his memory in Season 9 (Grey-Sloan Memorial)

Lexie Grey: Season 3-Season 8

Played by Chyler Leigh

Half-sister to Meredith Grey

Graduated from Harvard Medical School

Was in a plane crash in Season 8 that took her life

Had an on and off relationship with Mark Sloan

Has a photographic memory

Had the hospital named after her memory in Season 9 (Grey-Sloan Memorial)

Teddy Altman: Season 6-Season 8

Played by Kim Raver

Was in the army with Owen Hunt

Came to work at Seattle Grace in Season 6 as a Cardiothoracic Surgeon

Married a patient, Henry, in order for him to have insurance to cover a surgery

Fell in love with her husband in Season 7

Left in Season 8 when she was offered a job in the army

Ben Warren: Season 6-Season 9

Played by Jason George

Anesthesiologist working at Seattle Grace-Mercy West Hospital

Left Seattle Grace in Season in order to be a surgical intern at UCLA

Started dating Miranda Bailey in Season 7

Married Miranda Bailey in Season 9

Jo Wilson: Season 9

Played by Camilla Luddington

Surgical intern at Grey-Sloan Memorial

Confided in Alex Karev about her rough childhood

Developed a strong friendship with Alex Karev

Currently dating Jason Myers, an OBGYN at the hospital