Penelope Langston is a botanist and former analyst for the Tellis Naval group, as well as a former peace activist (and according to her son, Navy Admiral John McGee, a communist). She is the grandmother of NCIS Special Agent Timothy McGee and his younger sister, Sarah McGee as well as the widow of Nelson McGee and great-grandmother of Morgan and John McGee II.
Biography
Pre-Series
As McGee's grandmother, Penelope helped him develop confidence in himself, and to be himself regardless of what others thought of him - especially his father.
In 1968, Langston was invited to work as an analyst for the Tellis Naval group, and develop a project known as 'the Anax Principle'. She originally believed that her work was wholesome and would protect US soldiers serving in Vietnam. However, after a few years she realized she was working on a 'weapon of destruction'. The Anax Principle merged technology with nature by producing hybrid insects that were part machine. The idea was that these insects could be remotely controlled to infiltrate the crops of countries the US were at war with and create a genetically modified plague. This would devastate crop yields and cause famine, killing thousands and weakening enemy militaries. Upon realizing the unethical nature of her work, Langston decided to whistle blow the project. However, before she could expose the project, the war in Vietnam ended and the project was abandoned.
NCIS Season 9
NCIS Season 10
Personality
Penelope is very stubborn and loyal to her beliefs. When she sets her mind on something, it is very difficult to get her to see otherwise. Similar to her granddaughter, she seems to be aware of situations at hand but not take them as seriously as she should and believes that her past experiences have made her capable of handling any type of situation she may face; be it potential assassination or an interview from Gibbs.
Before and after marrying Tim's grandfather, she is a firm believer of being into somewhat "hippie" beliefs and has made clear statements of being against "Big companies and/or militaries" that only want to fill their wallets and leave the people to suffer.
Despite her stubborn nature, she shows that she does care about Tim and tries to protect him from certain things even though it might upset him.