Sofia Lamb was brought down to Rapture in 1950 by Andrew Ryan, who needed someone to calm the minds of the people still adjusting to living under the ocean. Before the move she was providing medical relief after the nuclear bombing of Hiroshima, which led her to believe that the surface world was doomed. Ryan later regretting bringing her down since her views clashed with his own. She believed in the power of the community rather than the self and that every person has a duty to the world. Ryan and Lamb frequently had public debates regarding their differences in ideals.
Her influence began corrupting the minds of the citizens of Rapture, and eventually an entire religion was set up honoring her as a Goddess. She gained an enormous amount of followers, lead by Father Simon Wales. Ryan, believing that Lamb was a threat to Rapture, hired Stanley Poole to spy on her and The Family (the group of Splicers devoted to her). Poole succeeded, and Lamb was sent to prison. However, she managed to take over the prison and escape.
Bioshock 2 begins with Subject Delta walking around with Eleanor, the Little Sister he was bonded to. However, one unfortunate event leads to another and Delta finds himself waking up 10 years later with no clue where Eleanor is. Lamb spent the 10 years rehabilitating Eleanor and turning her into "the People's Daughter". Throughout the game she remains in contact with Delta, often trying to spread her philosophy and beliefs to him.
Dr. Sofia Lamb's voice was provided by Fenella Woolgar.