When Robert F. Kennedy Jr. was considering potential running mates for his presidential run, his shortlist was initially topped

Instead, Mr. Kennedy made a surprise pick — a woman and a little-known figure with an unusual background: Nicole Shanahan.

Ms. Shanahan, 38, a onetime Silicon Valley lawyer, has never held public office and has scant name recognition. But she was selected after Mr. Rodgers and Mr. Ventura fell through as vice-presidential candidates and Mr. Kennedy’s campaign needed money to fund its efforts to get onto state ballots, three people familiar with the events said. And money was something that Ms. Shanahan could provide in abundance.

Ms. Shanahan has a fortune of more than $1 billion that stems largely from her divorce settlement last year with Sergey Brin, a founder of Google, whose net worth exceeds $145 billion, three people with knowledge of her finances said. During their five-year marriage, Ms. Shanahan partied with Silicon Valley’s elite and used recreational drugs including cocaine, ketamine and psychedelic mushrooms, according to eight people and documents reviewed by The New York Times. Ms. Shanahan and Mr. Brin separated after she had a sexual encounter with Elon Musk in 2021, three of the people said.

The incidents were part of a rarefied — and sometimes turbulent — life that Ms. Shanahan led in the nation’s tech capital before her turn to politics, according to interviews with more than 20 people who know her or were briefed on her actions, as well as property records, court documents, tax records, emails and other messages reviewed by The Times. Many of the details of her life, including those of her divorce settlement, have not been reported.