Imi Sde-Or (formerly, Imrich Lichtenfeld), founder of Krav Maga, was born in 1910 in Hungary and grew up in Bratislava, Slovakia.

Imi became active in a wide range of sports including gymnastics, wrestling, and boxing. In 1928, Imi won the Slovakian Youth Wrestling Championship, and in 1929 the adult championship (in the light and middle weight division). That year he also won the national boxing championship and an international gymnastics championship. During the ensuing decade, Imi's athletic activities focused mainly on wrestling, both as a contestant and a trainer.

Imi’s greatest influence was his father, Samuel, a police officer and self defense instructor. Samuel started his career as a circus acrobat and wrestler, but later entered the police department and served for 3 decades as Chief Detective Inspector. He became well known for his considerable arrest record, particularly of dangerous criminals.

When not on the trail of violent felons, Samuel taught various self defense techniques to the local policemen at “Hercules,” the first gym in Bratislava, which he owned.

In the mid thirties conditions began to change in Bratislava and Imi felt he had to take his fighting skills to the streets to protect Jewish neighborhoods from the growing numbers of fascist and anti-Semitic thugs who swarmed in Bratislava at the time. Imi quickly found however that although boxing and wrestling were good sports they weren't always practical for the aggressive and brutal nature of street fighting and he learnt the hard way that real life fighting was very different to competition fighting. It was then that he started to re-evaluate his ideas about fighting and started developing the skills and techniques that would eventually become Krav Maga. Imi left his home, family and friends in 1940 on the last refugee ship to escape Europe and the tightening Nazi noose. Imi reached Palestine where he began his tryst with the pre state Israeli military organizations which later became the Israeli Defense Forces in 1948 with the creation of the state of Israel. This association lasted more than 2 decades.

In 1964 Imi retired from the IDF and continued teaching Krav Maga to civilians, as well as law enforcement units and military applications. Upon his retirement Imi opened a school to teach a civilian form of Krav Maga, including a version suitable for youth. The first students to receive a black belt 1st Dan were Eli Avikzar, Rafi Elgarisi, Haim Zut (Haim Gidon was a student of Eli Avikzar), Shmuel Kurzviel, Haim Hakani, Shlomo Avisira, Vicktor Bracha, Yaron Lichtenstein, Avner Hazan and Miki Asulin.

In 1978, Lichtenfeld founded the non-profit Israeli Krav Maga Association (IKMA) with several senior instructors. Eli Avikzar was elected to the head of rank committee and Colonel David Ben Asher was elected to the Executive Director while Imi Lichtenfeld was elected as president 10th Dan. Since Imi at his old age was giving black belts to foreign students without Eli Avikzar's approval, Eli resigned from the association and created Krav Maga Israeli. Thereafter various civilian krav Maga associations were created. Lichtenfeld died in January 1998 in Netanya, Israel.