Karl was the second of three children born to Max and Sid Friedman. He attended Lakeview School and graduated from Ramsay High School at age 15. During his first year at the University of Alabama he enlisted in the U.S. Army for service in World War II. He trained as a P-47 Thunderbolt pilot and was deployed to England late in the war. He completed his service with the Judge Advocate General Corps, where he became interested in a career in law.
Friedman was accepted into the University of Alabama School of Law despite never completing his undergraduate degree. He graduated in 1948 with a class that included Howell Heflin, George Wallace, Tom Bevill, Armistead Selden and Richmond Flowers. He joined Morris Sirote, Jimmy Permutt and Edward Friend Jr in the new firm of Sirote & Permutt. He married the former Gladys Marie Cohen on September 5 of that same year.
Friend and Friedman were made partners of the firm of Sirote, Permutt, Friend, & Friedman in 1952. Friedman practiced primarily in business and banking law, but kept his door open for legal, business and personal counsel to uncounted clients and friends.
Friedman served as President of Temple Beth-El from 1961 to 1963, and as president of the Jewish Community Center of Birmingham from 1964 to 1968. He was also a founding director of the short-lived American National Bank, an organizer of the Birmingham Crisis Center, and a president of Goodwill Industries of Alabama.
Friedman also completed a novel, The Professor, which incorporates details drawn from his own life. It was published in 2000 by Elliott & Clark, an imprint of Black Belt Press in Montgomery.