Randall

Randall is Penny Hofstadter's, who appears to be older than her. Apart from Penny, he has another unnamed sister, and he is the only of Wyatt and Susan. He finally appeared in Season 10, but was previously only mentioned.

Overview
In "The Dumpling Paradox" (S01E07), Penny says that her Christy Vanderbel was  to her (Penny's) cousin while she was  her brother.

In "The Pirate Solution" (S03E04), it is revealed that he works in a and is described as a 'kind of ' and Penny told Leonard that Leonard would like her brother.

In "The Russian Rocket Reaction" (S05E05), Penny says that her family cat got stuck inside Randall's camp trunk.

In "The Rhinitis Revelation" (S05E06), Penny asks God to make her brother stop cooking but without involving the  when Sheldon's mother decides to get them to pray at a  church.

In "The Status Quo Combustion" (S07E24), Penny wants to schedule her 12 to 18  away so her brother can attend after he gets out of.

In "The Bachelor Party Corrosion" (S09E03), Penny's father tells Penny that her mother is out with her brother celebrating one month of being sober. He had also received his 10th one-month-sober chip.

It's revealed in "The Convergence-Convergence" (S09E24) that Penny's brother had been released from prison due to overcrowding, making him eligible to attend her redo wedding ceremony with the family.

In "The Conjugal Conjecture" (S10E01), Randall first appears in person and comes to Pasadena with his parents to attend the re-wedding. He smiles a lot and embarrasses his mother.

In "The Emotion Detection Automation" (S10E14), Penny mentions that she is trying to get him a job interview and needs a place to stay, which makes Leonard upset that she did this without telling him and causes an argument, but Leonard also gets really angry with Sheldon since it's the latter's fault the argument started.

Personality
Randall is sweet and cheery, if not somewhat dim. You might have trouble believing that he's the brother who went to prison for selling homemade crystal meth Penny talks about.

He also appears to embarrass people on a few occasions.

He also has no qualms about discussing his criminal background, much to the discomfort of his mother.

Family

 * Paternal Grandfather: Unnamed
 * Paternal Grandmother: Unnamed
 * Maternal Grandmother: Unnamed
 * Maternal Grandfather: Unnamed
 * Father: Wyatt
 * Mother: Susan
 * Sisters: Penny Hofstadter, Unnamed
 * Uncle: Unnamed
 * Cousin: Unnamed
 * Brother-in-laws: Leonard Hofstadter, Unnamed
 * Possible Son or Nephew: Unnamed