Lost cast and characters

Out of the 324 people on board, there were 72 initial survivors (71 humans and 1 dog) spread across the three sections of the plane crash. The opening season featured 14 regular speaking roles, making it the second largest cast in a currently-airing American prime time television show behind Desperate Housewives. While a large cast makes Lost more expensive to produce, the writers benefit from more flexibility in story decisions. According to series executive producer Bryan Burk, "You can have more interactions between characters and create more diverse characters, more back stories, more love triangles.&quot

The initial season had 14 major roles getting star billing. Naveen Andrews portrayed former Iraqi Republican Guard Sayid Jarrah. Emilie de Ravin played the pregnant Australian Claire Littleton. Matthew Fox acted as the troubled surgeon and protagonist Jack Shephard. Jorge Garcia portrayed Hugo "Hurley" Reyes, an unlucky lottery winner. Maggie Grace played Shannon Rutherford, a former dance teacher. Josh Holloway acted as con man James "Sawyer" Ford. Yunjin Kim played Sun-Hwa Kwon, the daughter of a powerful Korean businessman and mobster, with Daniel Dae Kim as her husband Jin-Soo Kwon. Evangeline Lilly portrayed fugitive Kate Austen. Dominic Monaghan acted as ex-rock star drug addict Charlie Pace. Terry O'Quinn played the mysterious John Locke. Harold Perrineau portrayed construction worker Michael Dawson, while child actor Malcolm David Kelley acted as his young son, Walt Lloyd. Ian Somerhalder played Boone Carlyle, chief operating officer of his mother's wedding business and step brother of Shannon.

During the first two seasons, some characters were written out to make room for new characters with new stories. Boone Carlyle was the first major character to be written out, dying near the end of season one. Walt became a guest star after the events of the first season's finale, making rare appearances throughout season two. Shannon's departure eight episodes into season two made way for newcomers Mr. Eko, a Nigerian Catholic priest and former criminal played by Adewale Akinnuoye-Agbaje; Ana Lucia Cortez, an airport security guard and former police officer played by Michelle Rodriguez; Bernard Nadler, a dentist and the husband of Rose; and Libby, a purported clinical psychologist portrayed by Cynthia Watros. Ana Lucia and Libby were written out of the series toward the end of season two.

In season three, Henry Ian Cusick received star billing as former Scottish soldier Desmond David Hume, as did Michael Emerson in the role of Ben Linus (formerly known as Henry Gale), a high ranking member of the "Others." In addition, three new actors joined the regular cast: Elizabeth Mitchell, as fertility doctor and "Other" Juliet Burke, and Kiele Sanchez and Rodrigo Santoro as background survivor couple Nikki Fernandez and Paulo. Eko was written out early in the season, and Nikki and Paulo were written out mid-season in their first flashback episode. Charlie was written out in the third season finale.

In season four, Harold Perrineau rejoins the main cast to reprise the role of Michael Dawson, now suicidal and on a desperate redemptive journey to redeem himself from his previous crimes. Along with Perrineau, additional new actors — Jeremy Davies as Daniel Faraday, a nervous physicist who takes a scientific interest in the island; Ken Leung as Miles Straume, a sarcastic supposed ghost whisperer, and Rebecca Mader as Charlotte Staples Lewis, a hard-headed and determined anthropologist and successful academic — have joined the cast. Claire, who mysteriously disappears with her dead biological father near the end of the season, will not return as a series regular for the fifth season. Michael is written out in the fourth season finale.

Numerous supporting characters have been given expansive and recurring appearances in the progressive storyline. Danielle Rousseau (Mira Furlan), a French member of an earlier scientific expedition to the island first encountered as a voice recording in the pilot episode, appears throughout the series; she is searching for her daughter, who later turns up in the form of Alex Rousseau (Tania Raymonde). In the second season, married couple Rose Henderson (L. Scott Caldwell) and Bernard Nadler (Sam Anderson), separated on opposite sides of the island (she with the main characters, he with the tail section survivors) were featured in a flashback episode after being reunited. The storylines regarding the fate of Desmond Hume led to the introduction of Penelope "Penny" Widmore (Sonya Walger), Hume's long-time girlfriend who has been searching for him since his disappearance, and her father, corporate magnate Charles Widmore (Alan Dale), whose destiny seems intertwined with the island's. The introduction of the "Others," inhabitants of the island, has featured such characters as Tom aka Mr. Friendly (M. C. Gainey), Ethan Rom (William Mapother), Goodwin Stanhope (Brett Cullen) and Richard Alpert (Nestor Carbonell), all of whom have been shown in both flashbacks and the ongoing story. The final days of the third season introduced Naomi Dorrit (Marsha Thomason), would-be rescuer with a mysterious freighter expedition, and Matthew Abbadon (Lance Reddick), apparently an employee of Widmore Industries. Jack's father Christian Shephard (John Terry) has appeared in multiple flashbacks of various characters, as has Anthony Cooper (Kevin Tighe), Locke's father and the man who conned Sawyer's parents, and many others.

In May 2007, it was announced that Lost would continue for its fourth, fifth, and sixth seasons, concluding with the 117th produced episode in May 2010. These three final seasons were planned to consist of 16 episodes each, running weekly in the spring uninterrupted by repeats. However, due to the 2007–2008 Writers Guild of America strike, the fourth season was shortened to 14 episodes, including a three-hour season finale. The fourth season premiered in the United States on January 31, 2008, and concluded on May 29, 2008. An additional consequence of the strike has been ABC's decision to extend the final two seasons of Lost by adding a seventeenth episode to each remaining season.