Lawrence started his professional career as a writer and published book, Deadly Force, the story later transform to a movie, A case of Deadly Force. Later, he started to serve as a legislative aide to Senator Daniel Patrick Moynihan, after working for some years he was promoted to senior advisor.
He also worked as staff director of the United States Senate Committee on Environment and Public works as well as staff director of the United States Senate Committee on Finance.
Moreover, O'Donnell also became a regular contributor to the program, Morning Joe along with Joe Scarborough. He also appeared frequently as a substitute host of Countdown with Keith Olbermann and The LastWord with Lawrence O'Donnell on MSNBC Network.
Furthermore, Lawrence worked as an editor of the television drama, The West Wing where he wrote numerous episodes. He won Emmy Award for Outstanding Drama Series for The West Wing. He also played Lee Hatcher character in the HBO series, Big Love, played President Josiah Bartlet's father in a flashback sequence in Two Cathedrals.
Moving towards his personal life, Lawrence O'Donnell married to television actress, Kathryn Harrold. They have a daughter, Elizabeth Buckley Harrold O'Donnell. They got divorced after 19 years of marital relationship. He is currently dating Tamron Hall and rumored of getting married soon.
Lawrence O'Donnell earns the handsome amount of money from his journalism career with the big chunk of annual salary. O’Donnell's current estimated Net worth is around $12 Million.