Orji Uzor Kalu attended Christ the King School Aba and Government College Umuahia. He also attended Barewa College, Zaria,and gain admission later at the University of Maiduguri where he studied political science. During his time at the university, Kalu became a student activist, and participated in the “Ali Must Go” riots against the education minister. His participation resulted in his suspension. While his fellow students later took the school authorities to court, Kalu left school to build his own business.

With only $35 to his name that he had borrowed from his mother, Kalu began trading palm oil, first buying the oil from Nigeria's eastern regions and then selling it in the country's northern regions. He then began buying and reselling furniture on a large scale.

Kalu eventually established SLOK Holding, a conglomerate that would consist of a number of successful companies, including the Ojialex Furniture Company, SLOK Nigeria Limited, SLOK United Kingdom Limited, Adamawa Publishers Limited, SLOK Vegetable Oil, Aba, SLOK Paper Factory, Aba, SLOK United States Incorporated, SLOK Ghana, Togo, Cotonou, Guinea, South Africa, Liberia, Botswana, SLOK Korea, Supreme Oil Limited, SLOK Airlines, Sun Publishing Limited, and First International Bank Limited.

Kalu became the youngest Nigerian to receive the National Merit Award from President Ibrahim Babangida, at the age of 26 in 1986. He was selected as the Nigerian Chamber of Commerce's Industrialist of the Year, and awarded the Humanitarian Award of the University of Nigeria, Nsukka's Humanitarian Club, the Volunteer Award of the International Association of Volunteers, the National Merit Award, the EU Special Award in Brussels, and the World Bank Leon Sullivan Award.

Kalu has a degree from Abia State University, a Certificate in Business Administration from Harvard University and honorary doctorates from the universities of Maiduguri and Abia State.

Kalu headed First International Bank Limited at the age of 33. He also stewarded Nigerian commercial relations with China's SinoPacific Shipbuilding company while serving as a principal of SLOK Holding.

On July 11, 2007, Kalu was arrested by the Economic and Financial Crimes Commission on charges of corruption while serving as the governor of Abia State. He was later released on bail, and accused the Obasanjo regime of persecuting him during and after his tenure in office, an accusation mentioned by former U.S. Ambassador to Nigeria John Campbell in his book, "Nigeria: Dancing on the Brink."

Kalu has been a staunch supporter of President Muhammadu Buhari, a "close friend and father, who deserves all the support to make Nigeria better."

Orji Uzor Kalu  is the chairman of SLOK Holding and the Daily Sun and New Telegraph newspapers in Nigeria, who served as the governor of Abia State, Nigeria from May 29, 1999, to May 29, 2007. Prior to his election, he served as the chairman of the Borno Water Board and the chairman of the Cooperative and Commerce Bank Limited. Kalu was also a member of the Peoples Democratic Party (PDP), Progressive Peoples Alliance (PPA) and the chairman of the PPA Board of Trustees. He was the party's presidential candidate in the April 2007 general election. He is currently a member of the ruling party after he officially announced his resignation as a PPA BOT.

Orji Uzor Kalu contested in the 2019 Nigerian general election to represent the people of Abia North in the senate, running under the banner of All Progressives Congress and won the secondary election.