Sheldon Cooper

All of our characters are in theory on the neuropsychiatric spectrum, I would say. Sheldon often gets talked about in terms of Asperger’s or OCD. He has a thing with germs, he has a thing with numbers, he’s got a lot of that precision that we see in OCD. There’s a lot of interesting features to all of our characters that make them technically unconventional socially.... And what we’re trying to show with our show is that this is a group of people who likely were teased, mocked, told that they will never be appreciated or loved, and we have a group of people who have successful careers, active social lives (that involve things like Dungeons and Dragons and video games), but they also have relationships, and that’s a fulfilling and satisfying life.

He has a genius-level IQ of 187 (in Young Sheldon his mother says that he has the same IQ as Albert Einstein and Stephen Hawking), but displays a fundamental lack of social skills, a tenuous understanding of humor, and difficulty recognizing irony and sarcasm in other people, although he himself often employs them. He exhibits highly idiosyncratic behavior and a general lack of humility, empathy, and toleration. These characteristics provide the majority of the humor involving him, which has caused him to be described as the show's breakout character. Some viewers have asserted that Sheldon's personality is consistent with Asperger syndrome and obsessive–compulsive disorder. Co-creator Bill Prady has stated that Sheldon's character was neither conceived nor developed with regard to any of these traits, although Parsons has said that in his opinion, Sheldon "couldn't display more traits" of Asperger's.

On July 16, 2009, Parsons was nominated for the Primetime Emmy Award for Outstanding Lead Actor in a Comedy Series. He was nominated again for the same award on July 8, 2010, and eventually won the award on August 29, 2010. On August 1, 2009, he won the TCA Award for Individual Achievement in Comedy, with the show itself winning the award for Outstanding Achievement in Comedy for season 2. He was nominated again for the same award in 2010 and 2012. Parsons was also nominated for the People's Choice Award for Favorite TV Comedy Actor and a Satellite Award for Best Actor – Television Series Musical or Comedy in 2009, 2010, and 2012. On January 16, 2011, Parsons won the Golden Globe Award for Best Actor – Television Series Musical or Comedy, presented by co-star Kaley Cuoco, for his work on seasons 3 and 4. On June 20, 2011, he won the Critics' Choice Television Award for Best Actor in a Comedy Series at the 1st Critics' Choice Television Awards for his work on season 4, and was nominated again for the same award in 2012. On September 18, 2011, he won his second consecutive Primetime Emmy Award – Lead Actor in Comedy, and was nominated again for the same award on July 19, 2012. In 2013, Parsons was nominated once again for the Golden Globe and received his first nomination for the Screen Actors Guild Award for Outstanding Performance by a Male Actor in a Comedy Series. In 2013 and 2014, Parsons was nominated for the Primetime Emmy Award – Lead Actor in Comedy for the 5th and 6th time, respectively, both of which he won for his 3rd and 4th Primetime Emmy Awards – Lead Actor in a Comedy Series meaning that Parsons had won this award 4 times in the last 5 years, including back-to-back in 2010/2011and 2013/2014. No actor, in the history of this award has won back-to-back awards on two separate occasions, and his total of 4 awards puts Parsons in a four-way tie at the top with comedy legends Carroll O'Connor, Kelsey Grammer, and Michael J. Fox.

He once idolized fictional prodigy Wesley Crusher from Star Trek: The Next Generation, portrayed by Wil Wheaton, until Wheaton did not show up at a convention attended by Sheldon in 1995. Sheldon had spent 15 hours on a bus travelling to the convention during which time he was forced to break his rule about urinating in a moving vehicle. After this moment Wil Wheaton became number six on Sheldon's mortal enemy list (a list he started when he was 9 on a 5¼-inch floppy disk). Wheaton was one of Sheldon's mortal enemies, along with his coworkers Barry Kripke and Leslie Winkle. Later, Wheaton managed to patch things up with Sheldon, only to inadvertently pass the enemy list spot to Brent Spiner. Sheldon would later resume his enmity with Wheaton in season 11's "The Proton Regeneration" when they compete for the lead role in an Internet reboot of Sheldon's childhood favorite science TV series, Professor Proton, and Wheaton gets the part; however, when he sees how well Wheaton plays the role and on the advice of Howard, he apologizes to him.

In "The Engagement Reaction", Sheldon mentions that his aunt Ruth died a week after being infected by a pathogen she contracted in the hospital where she visited Sheldon's uncle Roger, and that their ashes are now stored in a coffee can on Sheldon's mother's mantle. Young Sheldon confirms that Ruth is George's sister, and that she and Roger are still alive by 1990.

Sheldon Lee Cooper Ph.D., Sc.D., is a fictional character in the CBS television series The Big Bang Theory and its spinoff series Young Sheldon, portrayed by actors Jim Parsons in The Big Bang Theory and Iain Armitage in Young Sheldon (with Parsons as the latter series' narrator). For his portrayal, Parsons has won four Primetime Emmy Awards, a Golden Globe Award, a TCA Award, and two Critics' Choice Television Awards. The character's childhood is the focus of Young Sheldon: the series' first season is set in 1989 when nine-year-old prodigy Sheldon has skipped ahead five grades, to start high school alongside his older brother.

Sheldon was born in 1980 at Lawrence Memorial Hospital in Galveston, Texas, and raised in a small town in east Texas that is never named but is located a 3 hour drive from Dallas, along with his older brother, George Jr., and fraternal twin sister, Missy, by his mother, Mary Cooper, an overtly devout Baptist; and his father, George Cooper, a football coach. Sheldon once got his father fired when he told Mr. Hinckley, a store owner, that George was stealing from the cash register. In Young Sheldon, this is retconned: his father is a football coach who was fired from his coaching position in Galveston because he disclosed that other coaches were illegally recruiting players to their school, forcing the family to return to Medford, a fictional town in East Texas. He does drink, mostly beer, and is a loving father who is trying to understand his intellectually gifted son. The only member of his family to have actively encouraged his work in science was his maternal grandfather, whom he cherished and affectionately called "Pop-Pop", and who died when Sheldon was five years old. Pop-Pop's loss is what caused Sheldon to despise Christmas when his Christmas wish to bring Pop-Pop back did not come true. Sheldon's closest relative is his maternal grandmother whom he affectionately calls "Meemaw", and who in turn calls him "Moon Pie". His aunt was also said to have encouraged his work in science by giving him medical equipment, "in case his work in physics failed, he'd have a 'trade' to fall back on". In Young Sheldon, it is shown that his childhood friend Tam was the one who introduced him to non-scientific interests such as comic books and Dungeons & Dragons.