Born on June 15, 1973 in Albuquerque, NM, Harris was raised by his father, Ron, and mother, Sheila, both of whom were lawyers. He first caught the acting bug at age six, when he played Toto in a school production of “The Wizard of Oz.” While attending La Cueva High School, where he continued to perform in school plays, Harris met playwright Mark Medoff at a drama camp at New Mexico State University. Medoff cast the young Harris in “Clara’s Heart” (1988), playing a young boy dealing with his parent’s divorce while at the same time, cultivating a meaningful friendship with his Jamaican housekeeper (Whoopi Goldberg) – a role that earned him his first Golden Globe nomination. Over the next few years, Harris quickly racked up a number of television credits, including appearances in the TV movies "Too Good to Be True" (NBC, 1988) "Home Fires Burning" (CBS, 1989), "Cold Sassy Tree" (TNT, 1989) and a starring guest role in "Blues for Buder" (ABC, 1989), one of the "B.L. Stryker" detective TV movies, starring Burt Reynolds.
In 1989, Harris landed the role of the pubescent doctor on "Doogie Howser, M.D.,” likeably playing the 16-year-old medical school graduate who struggles to deal with both his patients and his adolescence. Thanks to his skillful, award-winning performance as the young idealistic medical professional, Harris became inextricably linked to the role, which threatened to limit his future career prospects after the series' 1992 demise. But Harris managed to keep busy with a slate of television appearances in long-forms and series guest roles. In 1991, he landed episodes of "Blossom" (NBC, 1990-95) and "The Simpsons" (Fox, 1989- ). The voice work on the latter prepared him for a regular starring role on the short-lived animated series "Capitol Critters" (ABC, 1992), playing Max, a country mouse who ends up in Washington, D.C. Featured guest parts on "Quantum Leap" (NBC, 1988-1993) and "Murder, She Wrote" (CBS, 1984-1996) were followed by playing a series of characters in fact-based television movies, most notably in "A Family Torn Apart" (NBC 1993) and "Snowbound: The Jim and Jennifer Stolpa Story" (CBS, 1994), in which he played a man who, along with his wife and five-month-old child, survives after days trapped in a Nevada avalanche.
Though mostly under the radar, Harris remained active in a series of television movies: "Not Our Son" (CBS, 1995), "My Antonia" (USA, 1995), "The Man in the Attic" (Showtime, 1995) and "Legacy of Sin: The William Coit Story" (Fox, 1995). After time away from television to pursue stage roles and feature work, Harris returned with a starring turn as a young successful businessman on a journey to self-discovery in the holiday offering, "The Christmas Wish" (CBS, 1998) and a supporting role the following year as King Charles VII opposite Leelee Sobieski in the miniseries, "Joan of Arc" (CBS, 1999). He returned to regular series work with "Stark Raving Mad" (NBC, 1999), playing the neurotic, germophobic editor of a zany horror novelist (Tony Shalhoub). The series' plum time slot – nestled between heavy-hitters "Frasier" (NBC, 1993-2004) and "ER" (NBC, 1994-2009) – and highly capable, watchable performances from Harris and Shalhoub failed to propel the otherwise by-the-numbers sitcom.
After a nine-year absence from film, Harris returned to the big screen with a supporting role in Paul Verhoeven's sci-fi actioner "Starship Troopers" (1997). After starring that same year alongside Matthew Lillard in the independent drama "The Animal Room” (1997), Harris essayed the role of a Harvard Law student who gets emotionally involved after being hired to sire the child of a successful, infertile couple (Madeline Stowe and William Hurt) in the 1930s-set drama "The Proposition" (1998). Back on stage, he played Romeo to Emily Bergl's Juliet in a 1998 Old Globe Theater production of the Shakespeare classic, then was touted by critics as a highlight of the Los Angeles concert version of the Sondheim musical, "Sweeney Todd” (2001). He returned to features with a supporting turn in "The Next Best Thing" (2000), which starred Madonna and Rupert Everett, respectively, as a woman and her gay male friend who suddenly find themselves as unwitting parents after an unexpected drunken night of sex.
Harris made another return to the stage, embarking on a highly successful run on Broadway by performing in such A-list productions as “Proof” (2001), opposite Anne Heche, and the 2003 revival of “Cabaret,” alongside Deborah Gibson and Tom Bosley. Drawing critical acclaim for his performance as the Emcee in “Cabaret,” Harris was tapped next to play the role of Lee Harvey Oswald in Stephen Sondheim's controversial musical, “Assassins” (2004). On the big screen, Harris delivered a hilarious cameo in “Harold & Kumar Go to White Castle” (2004), playing a sex-crazed, drug-addled parody of himself – a role he revived in the sequel, “Harold & Kumar Escape from Guantanamo Bay” (2008). The newly hot actor then landed a co-starring role as serial womanizer Barney Stinson on the hugely popular ensemble sitcom, “How I Met Your Mother” (CBS, 2005- ), about a married couple telling their children the story how they met and fell in love. An instant hit in the ratings, “How I Met Your Mother” had the residual effect of sparking the public’s interest in the personal lives of its stars. Harris, in particular, became a target of rampant gossip after it was rumored at the start of the second season that he was a closeted homosexual. After an initial denial from his publicist, Harris personally ended the mounting speculation with a statement to People magazine's website in November 2006: "Because of speculation and interest in my private life and relationships… [I] am quite proud to say that I am a very content gay man living my life to the fullest."
While a few Hollywood insiders wondered if his admission might hurt his career – especially in regards to his role as a womanizer on the top-rated sitcom – Harris enjoyed the exact opposite effect. Not only did ratings for “How I Met Your Mother” remain solid into its third season, Harris received his first Emmy nomination for Outstanding Supporting Actor in a Comedy Series in 2007, a feat he duplicated for the next two years. Meanwhile, in 2008, he earned his third Golden Globe nomination – his first for “How I Met Your Mother” – this time receiving a nod in the Best Supporting Actor category. In 2009, the fan favorite hosted the 63rd Annual Tony Awards, receiving overall glowing reviews by the harshest of critics. He was such a hit as Tony emcee, he was given the very prestigious job of hosting the 61st Annual Emmy Awards later that year.