While living in Los Angeles, screenwriters Jon Hurwitz and Hayden Schlossberg decided to write a low-budget stoner film and base the main characters on their high school friends from
Randolph High School. They based the character of Harold on their real-life friend Harold Lee. Hurwitz got the idea to base the film around White Castle from his own experience craving White Castle burgers when he lived in Pennsylvania for several years. At the time, Pennsylvania did not have any White Castle locations and Hurwitz had to have family members bring him frozen White Castle burgers from New Jersey. The filmmakers received permission from White Castle in 2002 to use the chain's name in the film. One scene that depicted a White Castle being closed was changed at the request of the company's director of marketing. Despite receiving top billing, Kal Penn revealed that he and John Cho did not get a big paycheck from the movie, with each only receiving a gross salary of $75,000 before numerous deductions to which Penn explained, "You deduct your taxes, 10% to your agent, 15% your manager, 5% to your lawyer, your publicity fees, and then your rent...And it averages out to probably about five-and-a-half months of living expenses once you've paid everybody and paid your taxes." Penn said that a working actor was likely to keep "maybe 30% of your paycheck" after paying taxes and service fees; his work from the movie left him with about $22,500 from his earnings.
Casting Hurwitz and Schlossberg included a role for Neil Patrick Harris as himself in the script without asking him first. Harris liked the script and agreed to appear in the film.
Ralph Macchio was the backup choice if Harris declined. Hundreds of actors auditioned for the title roles. They also approached John Cho and Kal Penn to try out the parts who were initially skeptical about the project. During casting, both Penn and actor
Sendhil Ramamurthy were being considered for the role of Kumar. After auditioning seven times, Penn eventually won the part. The role of Harold was between either Cho,
Bobby Lee,
Randall Park or
Dante Basco. Ryan Reynolds agreed to do a cameo in the film after working with Penn on
Van Wilder. They had been putting Harold and Kumar, who were Asian American, into all of their screenplays as the main characters, but had difficulty pitching to studios. "Our logic at the time was like nobody else is writing a stoner comedy about an [East] Asian dude and an Indian dude going to get White Castle," said Hurwitz, though director Danny Leiner remembered, "Before the casting and trying to get the money before Luke [Ryan, the executive producer] came on, we were going to a couple of the studios and one was like, "Look, we really love this movie. Why don't we do it with a white guy and a black dude?" Cho recalled, “It had to be rooted in that as a defense mechanism so that they wouldn’t get turned white." Schlossberg commented, "There had never been an Asian character without an accent except for [Cho] as the MILF guy. A lot of people read the script and just assumed they might be foreign exchange students, so you really had to emphasize that these guys were born in America. It was a totally different world." A few days before shooting the movie, Cho knocked on Penn's door and told him, "If we're supposed to be best friends, we'd better start hanging out together." They went to get a beer together and under artificial conditions, began a real friendship.
Filming Harold & Kumar began filming on May 12, 2003. The film is set in
New Jersey, but was mainly filmed in
Toronto, Ontario, Canada. Scenes set at
Princeton University were actually filmed at the
University of Toronto's
Victoria College and
Knox College. The production design team had to build a White Castle franchise especially for the shoot since Canada does not have White Castle restaurants. During filming, Penn ate veggie burgers as he is a vegetarian. ==Soundtrack==