Khalifa entered the pornographic film industry in October 2014 She had been working at a Whataburger when she was approached by a customer who asked if she had ever considered appearing in pornographic films. With more than 1.5 million views, the 22-year-old Khalifa became the most searched-for star on adult movie site Pornhub. On December 28 that year, Pornhub revealed that she was the #1 ranked porn star on their website.
Khalifa's newfound notoriety quickly drew strong criticism from many in the Middle East, who branded her career choice as shameful and Khalifa herself a disgrace to her country, especially for one of her videos filmed by Bang Bros, in which she is seen wearing a hijab. She received online death threats, including a manipulated image of a Islamic State of Iraq and the Levant executioner preparing to behead her, and a message warning her that she would go to Hell, to which she replied "I've been meaning to get a little tan recently". Lebanese newspapers wrote articles critical of Khalifa, which she considered trivial due to other events in the region.
In an interview with The Washington Post, Khalifa said the controversial scene was satirical and should be taken as such, claiming that Hollywood movies depicted Muslims in a far more negative light than any pornographer could. Among those who publicly spoke out to defend her decision to become an adult performer was British-Lebanese author Nasri Atallah, who stated, "The moral indignation ... is wrong for two reasons. First and foremost, as a woman, she is free to do as she pleases with her body. As a sentient human being with agency, who lives halfway across the world, she is in charge of her own life and owes absolutely nothing to the country where she happened to be born." Khalifa herself said of the controversy: "Women's rights in Lebanon are a long way from being taken seriously if a Lebanese-American porn star that no longer resides there can cause such an uproar. What I once boasted to people as being the most Westernized nation in the Middle East, I now see as devastatingly archaic and oppressed."
According to data from PornHub, from January 3 to 6, 2015, searches for Khalifa increased five-fold. Around a quarter of those searches came from Lebanon, with substantial searches also from nearby countries Syria and Jordan. Because of the hijab-related controversy, she was ranked #5 in a list of "The world's 10 most notorious porn stars" by British men's magazine Loaded in July 2016. Almaza, a Lebanese brewery, ran an advertisement showing a bottle of their beer next to Khalifa's signature glasses, with the slogan: "We are both rated 18+." In January 2015, electronic music duo Timeflies released a song titled "Mia Khalifa" in homage to her. In response, she posted a video to YouTube featuring herself twerking to the song.
In a July 2016 interview with The Washington Post, Khalifa revealed she had only performed in pornography for three months and had left the industry over a year before, changing to a "more normal job". She said "I guess it was my rebellious phase. It wasn’t really for me. I kind of smartened up and tried to distance myself from that."
