In 1876, he received his medical doctorate at Prague, and following graduation was a surgical assistant to Carl Wilhelm Heine (1838–1877). Afterwards he worked with Eduard Albert (1841–1900) at the Universities of Innsbruck and Vienna. In 1886, he became an associate professor in Vienna, and in 1891 was appointed professor of surgery at the Czech University in Prague.
Karel Maydl is remembered for the introduction of new surgical techniques, including a procedure for treatment of bladder exstrophy, as well as loop colostomy for use in cases of inoperable rectal cancer.