Mark Sloan found his Grey's Anatomy person in Lexie Gray. Plastic surgeon Mark (played by Eric Dane) joined Grey's in 2006's season 2 as Derek Shepherd's (Patrick Dempsey) best friend who had an affair with his then-wife. Derek was married to Addison Montgomery (Kate Walsh) ahead of the show before he found love with Meredith Grey (Ellen Pompeo) by the pilot. By the time Mark joined the Seattle Grace Hospital team, he was in no rush to settle down and often hooked up with a bevy of respective interns and nurses. He secretly had sex with Meredith's half-sister Lexie (Chyler Leigh) by season 5. The couple soon became endgame to fans before their tragic deaths in a season 8 plane crash. "I think they did a good job with that departure," Dane, who died in 2026 after battling ALS at age 53, told AOL during a Build Series interview in 2017. "I had a great time with [everyone, and I am] still friends with [Shonda Rhimes, the series creator] to this day." Eric Dane Died on 20th Anniversary of His 1st 'Grey's Anatomy' Episode Keep scrolling to revisit Mark and Lexie's complete relationship timeline: Clandestine Hookups In Mark's playboy era, he had sex with Lexie in season 5 during her intern year at Grey Sloan. "Teach me," Lexie asked Mark the first time they hooked up, taking off her T-shirt. "Teach me." He even notably snuck into her bedroom at Meredith's house multiple times after Meredith and Derek repeatedly warned him against pursuing the seemingly innocent Lexie. Hookups soon led to something more, including moving in together. The Arrival of Sloan Sloan Mark and Lexie were in for a shock during season 6 when Mark's long-lost daughter, Sloan (Levin Rambin), arrived and announced that she was pregnant. Mark leapt into dad mode and was eager to start a family with Lexie, Sloan and her baby. Lexie, however, wasn't ready to become an instant mom or grandma and broke up with Mark. Adam Larkey / (C)ABC / courtesy Everett Collection Separate Lives While Lexie dated the likes of Alex Karev (Justin Chambers) and Jackson Avery (Jesse Williams) amid her surgical residency, Mark primarily remained single aside from his brief hookups. He even had sex with longtime friend Callie Torres (Sara Ramirez) after her own breakup from Arizona Robbins (Jessica Capshaw) upon her move to Africa. A Brief Reunion Mark and Lexie reconciled only to discover that Callie was pregnant with daughter Sofia. Lexie broke up with Mark again for basically putting her in the same position twice, leading him to date ophthalmologist Julia Canner (Holley Fain). Amid Mark's romance with Julia, Lexie realized that she was still in love with her ex - even accidentally striking Julia in the chest with a softball during a pickup game. The Plane Crash Karen Neal / (C)ABC / courtesy Everett Collection Mark and Lexie were among the six Seattle Grace doctors aboard a private jet that crashed in the season 8 finale. The plane crash-landed in a forest, scattering the doctors around parts of the aircraft. Lexie was pinned underneath a jet, where she succumbed to her injuries while holding Mark's hand. Mark, who didn't want to leave Lexie's side, had just gotten to tell her that he dreamed of a future together with more kids, a house and a pet dog. Mark also sustained internal injuries in the crash, but he didn't die until being airlifted to Seattle Grace. The surviving doctors bought the hospital in season 9, renaming the facility Grey Sloan Memorial in Lexie and Mark's honor. A COVID-19 Fever Dream While Meredith was comatose with coronavirus in 2020's season 17, she had hallucinations of many of her late coworkers. Mark and Lexie showed up together in matching white outfits, urging Meredith to wake up and return to her family.