Born in Adelaide, Australia, LaPaglia was the son of immigrant parents; his Italian father, Eddie, was a car dealer and auto mechanic, and his Dutch mother, Maria, was a secretary. He set his sights on an acting career in his late teens, when he enrolled in the South Australian Castings Agency following his attendance at Rostrevor College. Though he only complete 18 months of a 30-month course, LaPaglia gained enough experience doing local community theater to pack his bags and forge ahead with a career in America. He settled in New York City, where he found success in the off-Broadway production, "Bouncers," in which he demonstrated his versatility and talent for accents while rendering eight different characters. LaPaglia quickly moved on to a series of guest appearances on popular television shows like "Amazing Stories" (NBC, 1985-87), "Magnum, P.I." (CBS, 1980-88), "Hunter" (NBC, 1984-1991) and "Trapper John, M.D." (CBS, 1979-1986). Following his feature debut in the cop thriller "Cold Steel" (1987), he landed the title role in the small screen biopic, "Frank Nitti: The Enforcer" (ABC, 1988), which detailed the story of the infamous Chicago crime boss post-Al Capone (Vincent Guastaferro) after he was sent to Alcatraz.LaPaglia next appeared in his first major film with a small role in James Ivory's "Slaves of New York" (1989), which followed the troubled lives and relationships of struggling New York City artists. He gained widespread attention for his scene-stealing performance in the mild comedy "Betsy's Wedding" (1990), playing the surprisingly courtly and charming nephew of a Mafia boss who romances the policewoman daughter (Ally Sheedy) of a Long Island construction contractor (Alan Alda). Though often typecast as an Italian bad guy, LaPaglia nonetheless remained steadily employed while he attempted to branch out. He delivered a dynamic performance as an all-too-lucky young man whose father (Danny Aiello) has conversely fallen on hard times, including owing debts to the mob, in "29th Street" (1991). Following supporting roles in "One Good Cop" (1991) and "He Said, She Said" (1991), LaPaglia played the cop friend of an unlucky-in-love San Francisco beat poet (Mike Myers) whose girlfriend (Nancy Travis) is suspected of being an axe-wielding psycho killer in "So I Married an Axe Murderer" (1993). After returning to off-Broadway stages for Steve Tesich's "On the Open Road" (1993), he had a supporting part as Barry 'The Blade', a flashy organized crime underling in the commercial courtroom suspense drama "The Client" (1994), starring Tommy Lee Jones and Susan Sarandon.Following a turn as a disenchanted Santa Claus in the Steve Martin comedy "Mixed Nuts" (1994), LaPaglia earned raves for his performance opposite Mercedes Ruehl in the Broadway revival of Tennessee Williams' "The Rose Tattoo" (1995) while delivering a critically-acclaimed performance as angst-ridden hit man in the independently made thriller, "Killer" (1994). Staying in the world where he was able to play a diversity of roles, he co-starred opposite perennial indie favorite Steve Buscemi for that actor's directorial debut, "Trees Lounge" (1996). LaPaglia increased his profile further with his first regular series role on the legal drama "Murder One" (ABC, 1995-97), joining the cast for the second and final season as Jimmy Wilder, a former district attorney-turned-defense counsel who willingly bends the law to his clients' needs. Back on the Great White Way, he earned further acclaim as Eddie Carbone in a revival of Arthur Miller's "A View from the Bridge" (1998), which earned the actor a coveted Tony Award. Taking a rare turn toward playing the bad guy in "Black and Blue" (1998), he played an abusive cop whose battered wife (Mary Stuart Masterson) tries to flee with her son, only to have him find them.Over the next several years, La Paglia appeared in several prominent features like "Summer of Sam" (1999) and "Sweet and Lowdown" (1999), while delivering a sterling performance as a cheating, alcoholic detective trying to uncover the mysterious disappearance and death of a woman in the twisting whodunit "Latana" (2001). Back on the small screen, he had an all-too-brief but memorable recurring stint on the popular sitcom "Frasier" (NBC, 1993-2004), playing the boorish brother of Daphne Moon (Jane Leeves), a role that earned him an Emmy for Outstanding Guest Actor in a Comedy Series in 2002. That same year, he appeared as a crooked cop dealing with a group of meth addicts in "The Salton Sea," while starring alongside Keifer Sutherland in the action movie "Dead Heat." He next starred opposite Sigourney Weaver in "The Guys" (2002), a film inspired by the heroism of New York City firefighters during the 2001 attacks on the World Trade Center, while being underused in the rather forgettable romantic comedy "I'm With Lucy" (2002). After years of solid performances and the respect of his professional peers, LaPaglia finally achieved mainstream recognition when he took on the lead role of troubled FBI Missing Persons investigator Jack Malone in the popular television crime drama, "Without a Trace" (CBS, 2002-09). Though good at his job, Malone often suffered from personal travails - namely in the form of a bitter divorce proceeding with his wife, who used everything she could to gain custody of his two daughters (Laura Marano and Vanessa Marano). A highly-rated show that ran for seven long and lucrative seasons, "Without a Trace" earned LaPaglia a Golden Globe for Best Performance by an Actor in a Television Series Drama in 2004. While on the show, LaPaglia maintained his film career, playing a once promising writer hiding in the shadows of his famous author father in the low-budget indie, "Happy Hour" (2003). He next gave a strong performance as a New Jersey widower trying to get on with life along with his two teenage sons (Aaron Stanford and Mark Webber) in the well-reviewed ensemble drama, "Winter Solstice" (2005). After voicing Boss Skua in the Australian-made animated feature "Happy Feet" (2006), LaPaglia was "The Architect" (2006) who falls under fire by tenants of a housing complex he designed while struggling to keep his family together. He next voiced the Great Gray Owl Twilight in the animated "Legend of the Guardians: The Owls of Ga'Hoole" (2010), followed by a reprise of his earlier animated role in "Happy Feet 2" (2011). LaPaglia next appeared in the indie romantic comedy "Overnight" (2012) and writer/director P.J. Hogan's comedy-drama "Mental" (2012). A key role in the biopic "Underground: The Julian Assange Story" (2012) was followed by a lead opposite Joan Allen in the Stephen King thriller "A Good Marriage."