Jordan graduated magna cum laude from Texas Southern University in 1956 and from Boston University Law School in 1959. She passed the bar exams in Massachusetts and Texas before returning to Houston to open a law practice, only the third African-American woman to be licensed in Texas.
Jordan campaigned for the Texas House of Representatives in 1962 and 1964. Her persistence won her a seat in the Texas Senate in 1966, becoming the first African American state senator since 1883 and the first black woman to serve in that body. Re-elected to a full term in the Texas Senate in 1968, she served until 1972. She was the first African-American female to serve as president pro tem of the state senate and served for one day as acting governor of Texas in 1972.
In 1972, she was elected to the United States House of Representatives, becoming the first black woman from a Southern state to serve in the House. She received extensive support from former President Lyndon Johnson, who helped her secure a position on the House Judiciary Committee. In 1974, she made an influential, televised speech before the House Judiciary Committee supporting the impeachment of President Richard Nixon.
Jordan was mentioned as a possible running mate to Jimmy Carter in 1976,, and that year she became the first African-American woman to deliver the keynote address at the Democratic National Convention. Her speech in New York that summer was ranked 5th in "Top 100 American Speeches of the 20th century" list and was considered by many historians to have been the best convention keynote speech in modern history until the 2004 keynote by Barack Obama.
Jordan retired from politics in 1979 and became an adjunct professor at the University of Texas at Austin Lyndon B. Johnson School of Public Affairs. She again was a keynote speaker at the Democratic National Convention in 1992.
In 1995, Jordan chaired a Congressional commission that advocated increased restriction of immigration and increased penalties on employers that violated U.S. immigration regulations. President Clinton endorsed the Jordan Commission's proposals.