From Wikipedia

Baker was born to Catholic parents, high school English/Drama teacher Elizabeth Labberton and groundskeeper/mechanic Barry Baker, on July 30, 1969, in Launceston, Tasmania, Australia. His parents divorced while he was still young and his mother later married butcher Tom Denny. Baker also has a sister, currently a doctor in Australia, and three younger half siblings. By 1972, they had moved from Launceston, Tasmania to Ballina, New South Wales, Australia, hoping to secure better paying jobs. In 1986, he graduated from Ballina High School.

Baker was a champion sportsman who competed at state level in surfing and water polo. He began acting on Australian television during the late 1980s using the name "Simon Baker Denny". He first appeared in music video clips for Melissa Tkautz ("Read My Lips") and Aussie dance outfit Euphoria ("Love You Right") in 1991 before appearing in the successful series E Street and Heartbreak High. Baker relocated to the United States where he was occasionally known by his stepfather's surname (as Simon Baker-Denny or Simon Denny).

He was cast in a small but important part as a young would-be actor in L.A. Confidential, which led to further opportunities in supporting roles in films. In 1998 he starred in a small, independent film by filmmaker Stephen Grynberg titled "Love from Ground Zero". In 2000 he played an astronaut in Red Planet with Val Kilmer, Carrie Anne Moss and Benjamin Bratt. He played the male lead in the television series The Guardian for three seasons beginning in 2001, and also appeared in The Affair of the Necklace. He played a distressed husband in 2004's Book of Love. In 2005, he starred as an altruistic hero in George A. Romero's Land of the Dead.

In 2006, he played Brian Kelly in the film Something New, writer Christian Thompson in The Devil Wears Prada and had a leading role as Jeff in the short-lived television series Smith. That following year, he was cast as Roderick Blank in Sex and Death 101.

In 2008 Baker received the lead role in the CBS television series The Mentalist in which he plays a consultant to the California Bureau of Investigation (CBI), skilled in picking up the details of body language and visual clues of suspects' appearances. His character is further darkened by a history of mental trauma following the murder of his wife and child, which drives him in his work. In 2009, Baker was nominated for an Emmy for his work in The Mentalist.

Baker is married to Australian actress Rebecca Rigg (m. 1998 to present) and has three children; Stella Breeze, Claude Blue, and Harry Friday. According to a recent interview with David Letterman on the Late Show, Baker made mention of the fact that fellow Australian actors Nicole Kidman and Naomi Watts are godparents to two of his children. Until recently Baker and his family resided in Malibu, California, before temporarily moving back to Sydney, New South Wales, Australia. They have since returned to Los Angeles.

In February 2009, Baker appeared on the The Ellen DeGeneres Show and said that he was applying to become an American citizen.