Season 4 (Supergirl)

was renewed for a fourth season by The CW on April 2, 2018. It premiered on October 14, 2018.

Main cast

 * Melissa Benoist as Kara Danvers/Supergirl and Kara Danvers
 * Mehcad Brooks as James Olsen
 * Chyler Leigh as Director Alex Danvers and Alex Danvers (Earth One)
 * Katie McGrath as Lena Luthor
 * Jesse Rath as Querl Dox/Brainiac 5
 * Sam Witwer as Ben Lockwood/Agent Liberty
 * Nicole Maines as Nia Nal/Dreamer
 * April Parker Jones as Colonel Lauren Haley
 * David Harewood as J'onn J'onzz

Recurring cast

 * Brenda Strong as Lillian Luthor
 * Andrea Brooks as Eve Teschmacher
 * Jeremy Jordan as Winn Schott
 * David Ajala as Manchester Black
 * Tiya Sircar as Fiona Byrne
 * Rhona Mitra as Mercy Graves
 * Robert Baker as Otis Graves
 * Lynda Carter as Olivia Marsdin
 * Bruce Boxleitner as President Baker
 * Anthony Konechny as Raymond Jensen/Parasite
 * Xander Berkeley as Peter Lockwood
 * Jon Cryer as Lex Luthor
 * Azie Tesfai as Kelly Olsen
 * Hannah James as Maeve Nal
 * Jessica Meraz as Pamela Ferrer/Menagerie

Confirmed plot points

 * There will be an Elseworlds crossover with The Flash and Arrow. The crossover will introduce Batwoman and Gotham City.
 * Journalism is going to be a big part of the season.
 * The theme of the season is, "What Is Stronger; Hope or Fear?"
 * The Red Son-ish cliffhanger from the Season 3 finale will become a big centerpiece in the latter part of the season.
 * This season, Brainiac will socially butt heads with a couple people.
 * Mehcad Brooks hinted that there will be "fallout" from James choosing to unmask himself as Guardian last season.
 * What will the characters make of Kate Kane aka Batwoman, in this December's Arrowverse crossover? "I think Alex might really like her", EP Sarah Schechter surmised with a smile. "I think strong women like each other, and strong women support each other. They definitely have very different ways of behaving in the world, but I think, ultimately, they'll agree that women should be in charge".
 * David Harewood will direct an episode this season.
 * Lex Luthor will be introduced this season.
 * James Olsen's sister will appear this season.
 * Nia Nal's mother and sister will appear this season.
 * Manchester Black will form a group called "Elite".

Confirmed new characters

 * Lex Luthor: He will shake things up in National City and go toe to toe with not only Supergirl, but his sister Lena Luthor.
 * Kelly Olsen: Kelly is an intelligent and insightful woman who spent time in the military in order to pay for medical school. She's recently discharged from the military and is currently finishing her training as a psychiatrist. She's got a large heart and cares deeply about others.
 * Maeve Nal: Driven and focused on maintaining the Nal family’s rich legacy. She and Nia have a strong sisterly bond, although Maeve has always had to work harder to achieve what comes naturally to Nia.
 * Isabel Nal: The warm and nurturing mother of Nia Nal, is a local hero in her own right. She is a wise and generous matriarch and has raised her family to be bold and courageous, as well as to love fiercely and openly.
 * Pamela Ferrer/Menagerie: A member of Manchesters Black’s “Elite,” Menagerie is a jewel thief who doesn’t mind hurting people.

Trivia

 * This season airs on Sundays at 8/7c, as opposed to the past three seasons, where it aired on Mondays at the same time.