Iain Armitage as Sheldon Cooper, a 9 - year - old child prodigy with a "once - in - a-generation mind capable of advanced mathematics and science ''. While well - versed in all types of math and science, he is shown to prefer theoretical physics, stating that he decided to pursue the field around the same time as the show began. While academically gifted, Sheldon lacks a full understanding of social cues and behaviors, in addition to having a sense of superiority over everyone around him due to his intelligence. Sheldon is prone to travel his own path even if he gets into trouble along the way. Nevertheless, Sheldon has proven to love his family and almost always has his heart in the right place. Zoe Perry as Mary Cooper, Sheldon 's mother. She is very protective and patient with Sheldon but also struggles to understand him at times. She is a devout Christian and so has friction with Sheldon 's atheism and derision of Christianity. Nevertheless, she deeply loves her son and wants to protect him for as long as she can. Lance Barber as George Cooper Sr., Sheldon 's father and the head football coach at Medford High. While often a voice of reason, George is not the brightest member of the family, leading others, especially Meemaw, to doubt him being Sheldon 's father. While he may struggle with understanding his intellectually gifted son, George is a loving father and has defended Sheldon on multiple occasions, earning Sheldon 's love and appreciation. Montana Jordan as George "Georgie '' Cooper Jr., Sheldon 's older brother. Georgie openly despises Sheldon and never hesitates to bully him. He is not very intelligent and so is mocked and teased by the rest of the family, particularly Sheldon and Meemaw. While he is outwardly confident in himself, Georgie hides deep insecurities over feeling inferior to his genius brother and thus copes by trying to belittle Sheldon 's intelligence in any way he can. He attends Medford High with Sheldon and plays on the football team. Raegan Revord as Missy Cooper, Sheldon 's twin sister. She teases Sheldon along with Georgie but not as much. She does not share Sheldon 's intelligence but is very perceptive. While she does not always get along with Sheldon, she finds in her twin brother a solid confidant and has admitted to not feel as whole without him. Jim Parsons as the voice of adult Sheldon Cooper, who narrates the series as the older, present - day version of the character. Annie Potts as Constance ' Connie ' Tucker, Sheldon 's maternal grandmother, known to him as "Meemaw ''. She is very close with Mary and her grandchildren but does not think highly of George and often jokes about him. She is the most patient and understanding of Sheldon 's quirks and advises Mary to trust that Sheldon will find his way.
who plays sheldon's father on young sheldon
Lance Barber