CBS' The Big Bang Theory centered around nerdy scientists and roommates Leonard Hofstadter and Sheldon Cooper and their interactions with their next-door neighbor, Penny, and their equally nerdy friends, Howard Wolowitz and Raj Koothrappali. Over the course of 12 seasons, the show saw several new characters join the main cast. The most significant additions were neuroscientist and Sheldon's eventual wife, Amy Farrah Fowler, microbiologist and Howard's eventual wife, Bernadette Rostenkowski, and comic store owner Stuart Bloom.
But before characters like Amy and Bernadette were introduced to the series, The Big Bang Theory had a different female scientist join the group for a brief period: Leslie Winkle. However, after being a crucial part of the show for three seasons, she would vanish, leaving many to wonder what happened to the character.
Who Was Big Bang Theory's Leslie Winkle
Portrayed by actress Sara Gilbert, Leslie was a physicist who was introduced in Season 1 as a potential love interest for Leonard. Feeling hopeless in his pursuit of Penny, Leonard attempted to pursue a relationship with Leslie due to their shared intellect. Though the two ended up in bed together, she later revealed she only used him for sex and had no interest in being his girlfriend. Leslie would go on to appear several times throughout the first season, usually to antagonize Sheldon.
Leslie was promoted to main character status in Season 2, despite being absent for several episodes. Much of her storyline revolved around her rivalry with Sheldon and Leonard's failed attempts at starting a relationship with her. She even began a brief "friends-with-benefits" relationship with Howard, only to dump him unceremoniously over the phone later in the season. After this, her character was cut out of Season 3 almost entirely, only appearing in the season finale to once again reject Leonard's advances.
Why Leslie Winkle Left The Big Bang Theory
After her brief appearance in Season 3, Leslie vanished from the series and Amy and Bernadette became the show's primary female scientists. Though the creators of the show never officially confirmed why Leslie stopped appearing, insiders who spoke to Entertainment Weekly back in 2009 stated that, because producers weren't able to generate enough storylines for the character, she was written off the show. Since her time on The Big Bang Theory, Sara Gilbert has continued to work in television, going on to create, co-host and executive produce CBS' The Talk and star in ABC's reboot of Roseanne and its spin-off The Conners.
After a six-year absence, Leslie would return to The Big Bang Theory for the show's 200th episode, Season 9's "The Celebration Experimentation." When Sheldon's friends decided to throw him his first birthday party in years, Leslie was one of the many guests invited to the party. After reconnecting with Leonard, she gave a toast to Sheldon, stating that despite their rivalry in the past, she wanted him to have a happy birthday.