Neeson was born in Ballymena, County Antrim, Northern Ireland, June 7, 1952 the son of Katherine "Kitty" Neeson (ne Brown), a cook, and Bernard "Barney" Neeson, a caretaker at the Ballymena Boys All Saints Primary School.[4] He was raised Roman Catholic[5][6][7] and was named Liam after the local priest.[8] The third of four siblings, he has three sisters: Elizabeth, Bernadette, and Rosaline.[9] At age nine, Neeson began boxing lessons at the All Saints Youth Club and later became Ulster's amateur senior boxing champion.[10] Neeson first stepped on stage at age 11 after his English teacher offered him the lead role in a school play, which he accepted because the girl he was attracted to was starring in it.[11] From then on, he kept acting in school productions for the following years.[12]

His interest in acting and decision to become an actor was also influenced by minister Ian Paisley, whose Presbyterian church Neeson would sneak into. Neeson has said of Paisley: "He had a magnificent presence and it was incredible to watch him just Bible-thumping away... it was acting, but it was also great acting and stirring too."[13] In 1971, Neeson was enrolled as a physics and computer science student at Queen's University Belfast, Northern Ireland, before leaving to work for the Guinness Brewery.[14] Also at Queen's, he discovered a talent for football and was spotted by Sen Thomas at Bohemian F.C. There was a club trial in Dublin and Neeson played one game as a substitute against Shamrock Rovers, but he was not offered a contract.[15]

After leaving the university, Neeson returned to Ballymena where he worked in a variety of casual jobs, from a fork-lift operator at Guinness to a truck driver. He also attended teacher training college for two years in Newcastle upon Tyne, before again returning to his hometown. In 1976, Neeson joined the Lyric Players' Theatre in Belfast where he performed for two years. He got his first film experience in 1977, playing Jesus Christ and Evangelist in the religious film Pilgrim's Progress. Neeson moved to Dublin in 1978 after he was offered a part in Ron Hutchinson's Says I, Says He, a drama about The Troubles, at the Project Arts Centre. He acted in several other Project productions and joined the Abbey Theatre (the National Theatre of Ireland).

Neeson guest-starred in the third season of the television series Miami Vice in 1986 and moved to Hollywood to star in more high-profile roles in the next year.[16] That year, he starred alongside Cher and Dennis Quaid in Suspect in a role that brought him critical acclaim. Director Steven Spielberg offered Neeson the role of Oskar Schindler in the film about the Holocaust, Schindler's List,[17] after seeing him in Anna Christie on Broadway. His critically acclaimed performance earned him a nomination for a Best Actor Oscar, and helped the film earn Best Picture of 1993. Neeson also garnered BAFTA and Golden Globes nominations for his work as Oskar Schindler. Soon after these accolades, Neeson became an in-demand leading actor. Many offered he received, like became actor of "Star Wars Episode I: The Phantom Menace" 1999, "Love Actually", "Batman Begins, "Chloe", "Clash of the Titans", "The A-Team", and Taken.

In private life, Liam is a devoted husband and loved-father. As he was the husband of the Natasha Richardson (married July 3, 1994), who died cause of cerebral hemorrhage two days after a skiing accident on March 16, 2009. From the marriage has been 15 years, Liam and Natasha had two sons called Micheal Richard Antonio (June 22, 1995) and Daniel Jack (August 28, 1996)