Qadhi has written numerous books and lectured widely on Islam and contemporary Muslim issues. A 2011 New York Times Magazine essay by Andea Elliott described Qadhi as "one of the most influential conservative clerics in American Islam."
Qadhi was born in Houston to parents of Pakistani origin. When Qadhi was five, the family moved to Jeddah, Saudi Arabia, where he attended local schools. He graduated from high school two years early as class valedictorian. He returned to the United States, where he earned a B.Sc in Chemical Engineering at the University of Houston.
At 17, Qadhi became influenced by the Salafi teacher Ali al-Tamimi. Qadhi studied under al-Tamimi. Years later in 2010 he stated that al-Tamimi "played an instrumental role in shaping and directing me to take the path that has led me to where I am today." Al-Tamimi was sentenced in July 2005 to life imprisonment in the United Kingdom for inciting terrorism.
After a short stint working in engineering at Dow Chemical, in 1996 Qadhi enrolled at the Islamic University of Medina in Medina, Saudi Arabia. There, he earned a bachelor's degree in Arabic from the university's College of Hadith and Islamic Sciences and a master's degree in Islamic Theology from its College of Dawah.
Qadhi returned to the United States in 2005 after working and studying for nine years in Saudi Arabia. He completed a doctorate in theology at Yale University in New Haven, Connecticut.
Qadhi teaches in the Religious Studies Department of Rhodes College, in Memphis, Tennessee. He also has served since 2001 as the Dean of Academic Affairs and an instructor for the AlMaghrib Institute. This is a seminar-based Islamic education institution founded in 2001. The instructors travel to designated centers in the US (Houston, Texas), Canada (Ottawa, Ontario), and the UK (London) to teach Islamic studies in English. A center has been added in Malaysia.
Qadhi notes that some of the practices he endorses are similar to those practiced by conservative Christian groups and Orthodox Jews in the United States. For instance, he says that each group observes dietary laws (which sometimes cover acceptable drinks), stress family values, and require modest dress for women.
Qadhi was a guest subject on an episode of Harvard professor Henry Louis Gates's television genealogy series Finding Your Roots on PBS.
Qadhi has presented papers on jihad movements. In 2006, at a conference at Harvard Law School, Qadhi presented a 15-minute analysis of the theological underpinnings of an early militant movement in modern Saudi Arabia headed by Juhayman al-Otaibi. The movement had gained international attention when it held the Grand Mosque of Mecca hostage in 1979.
In September 2009, he presented a paper at an international conference at the University of Edinburgh on understanding jihad in the modern world. He discussed how the specific legal ruling (fatwā) of the 13–14th century theologian Ibn Taymiyya has been since used in the 20th and 21st centuries by both jihadist and pacifist groups to justify their positions. The paper has been critiqued, by some Salafi commentators.
Qadhi is a critic of extremist violence and believes that terrorism is antithetical to Islamic values. He tackles political grievances of Muslims. He has criticized United States foreign policy, which he believes many Muslims object to in terms of US actions in Muslim countries. He has also criticized how extremists use religious claims to justify their violence.
In the April 2016 issue of Dabiq Magazine, the Islamic State of Iraq and the Levant declared Qadhi, along with Hamza Yusuf, Bilal Philips, Suhaib Webb and numerous other Western Islamic scholars, as murtadds (or apostates). It threatened to kill them for denouncing ISIS and the shooting attacks in Paris on the Charlie Hebdo offices.
In January 2010, the British The Daily Telegraph reported that in 2001 Qadhi had described the Holocaust as a hoax and false propaganda, and had claimed that "Hitler never intended to mass-destroy the Jews." The following year, the New York Times recounted his claim that most Islamic studies professors in the United States are Jews who “want to destroy us.”
Qadhi denied stating that the Holocaust was a hoax or that it was false propaganda, but in 2008 admitted that he had briefly held mistaken beliefs about the Holocaust, and had said "that Hitler never actually intended to massacre the Jews, he actually wanted to expel them to neighboring lands". Qadhi acknowledged that his views were wrong and said "I admit it was an error".
Qadhi added that he firmly believes "that the Holocaust was one of the worst crimes against humanity that the 20th century has witnessed" and that "the systematic dehumanization of the Jews in the public eye of the Germans was a necessary precursor" for that tragedy. More generally, he has admitted that he "fell down a slippery slope", expressing anger at actions of the Israeli government in the form of anti-Semitic remarks he later recognized as wrong.
In July 2010, Qadhi was selected to participate in an official delegation of eight U.S. imams and Jewish religious leaders to visit the concentration camps at Auschwitz and Dachau. The imams subsequently released a joint statement condemning anti-Semitism and labeling Holocaust denial as against the ethics of Islam.
Books authored or co-authoredRiyaa: Hidden Shirk, 103 pages, Dar-al-Fatah, 1996, ISBN 8172317530
An Introduction to the Sciences of the Qura̓an, Al-Hidaayah Pub., 1999, ISBN 1-898649-32-4
An Explanation of the Four Principles of Shirk, 60 pages, with Muḥammad ibn ʻAbd al-Wahhāb, Al-Hidaayah, 2000, ISBN 1-898649-52-9
Du'a : The Weapon of the Believer, Al Hidaayah Publishing & Distribution, 2001, ISBN 1-898649-51-0
15 Ways to Increase Your Earnings from the Quran and Sunnah, Al Hidaayah Publishing & Distribution, 2002, ISBN 1-898649-56-1
An explanation of Muhammad ibn Abd al-Wahhab's Kashf al-Shubuhat: a critical analysis of shirk, with Muḥammad ibn ʻAbd al-Wahhāb, Al-Hidaayah, 2003, ISBN 1-898649-62-6