Of Lebanese descent, Abourezk was born in Wood, South Dakota and lived in South Dakota most of his life. Between 1948 and 1952, he served in the United States Navy during the Korean War. Back in the U.S., he received a degree in civil engineering from South Dakota School of Mines in Rapid City, South Dakota in 1961, and then earned an advanced degree from University of South Dakota School of Law in Vermillion in 1966. He passed the bar, and began a legal practice in Rapid City.

He was elected as a Democrat to the House of Representatives, and served from 1971 to 1973. He then was elected to the U.S. Senate, where he served until 1979. In the Senate, he was preceded by Karl Earl Mundt, and followed by Larry Lee Pressler after he chose not to run for reelection. There, he was the chair of the Select Committee on Indian Affairs and of the American Indian Policy Review Commission. He earned a reputation as a maverick who questioned the political status quo.

In 1980, Abourezk founded the American-Arab Anti Discrimination Committee, a grassroots civil rights organization committed empowering Arab-Americans and encouraging a balanced U.S. foreign policy in the Middle East. In 1989, he wrote Advise and Dissent: Memoirs of South Dakota and the U.S. Senate (ISBN 1556520662) and he is the co-author of "Through Different Eyes: Two Leading Americans - a Jew and an Arab - Debate U. S. Policy in the Middle East."

In a 2006 interview, Abourezk called the groups Hamas and Hezbollah "resistance fighters", and said that America's support of Israel endures because "the Congress is pretty much reliant on money from radical Zionists".

Abourezk now works as a lawyer and writer in Sioux Falls, South Dakota.