The founder of the early school of Eishin-ryu is Hayashizaki Minamoto no Shigenobu (1546-1621). Hayashizaki was born in Oshu, Dewa Province (present-day Yamagata Prefecture). Many of the historical details of Hayashizaki's life are highly suspicious. It is assumed that he grew up during the constant wars in Japan and for this reason began to study sword fencing techniques from a very young age. According to legend, the reason for serious and scrupulous training was a desire to avenge the death of his father. To do this, Hayashizaki retired to the temple, where he prayed for a long time and ultimately received divine inspiration, thanks to which he developed new sword fencing techniques and a one-move attack method. Legend has it that he eventually took revenge on his father's killer.

After Hayashizaki continued on his way, studying with famous swordsmen and making his own students (for example, Tamiya Heibei, founder of Tamiya-ryu) . He called his own style Shinmei Muso-ryu. In general, Hayashizaki's art has had many names since its inception. For example, it was referred to as Hayashizaki-ryu or Yusin-ryu. His style greatly influenced the development of the main iai styles practiced today, such as Muso Jikiden Eishin-ryu and Muso Shinden-ryu.

The seventh head of the Hayashizaki school, Hasegawa Chikaranosuke Hideenobu (Eishin), is one of its most important representatives. He had a significant impact on the school's technical arsenal. In particular, he adapted the techniques originally developed for the tachi to use the modern katana . In addition he added many new techniques , some of which formed the Tatehidza no Bu kata. All this led to the fact that the style was renamed to Hasegawa Eishin-ryu. In addition, he was also referred to as Hasegawa-ryu or simply Eishin-ryu.

Some consider Hasegawa the main founder of the Eishin-ryu style, which makes him the first generation of soke, and not the seventh , and the Shinmeyo Muso-ryu school is the progenitor of Muso Jikiden Eishin-ryu. Hayashi Rokudayu Morimasa became the ninth head of the school. He introduced into the curriculum a set of methods practiced from a sitting position - seiza. Presumably, these methods were developed by Hayashi's kenjutsu teacher, Shinkage-ryu swordsman Omori Rokurozaemon , and are said to be influenced by the foundations of Ogasawara-ryu school etiquette . It was Hayashi who was responsible for representing the school in the Tosa principality at the request of the ruling Yamauchi family . After the school took root in Tosa, it became known as Tosa Eishin-ryu . The Eishin-ryu and Omori-ryu styles were taught by members of the Yamauchi family with several characteristics.

After the death of the 11th soke Oguro Motozaemon, the school was split into two branches. Later they became known as Tanimura-ha and Shimomura-ha.

One of the most important soke of the Muso Jikiden Eishin-ryu school is the 17th generation guardian of tradition, Oe Masaji. He was born in Asahi Tosa in 1852. As a young man, Oe studied styles such as Kokuri-ryu and Oishi Shinkage-ryu, along with Shimomura-ha Eishin-ryu (Muso Shinden Eishin-ryu). At the age of 15, he took part in the Battle of Toba - Fushimi, after which he studied Tanimura-ha Eishin-ryu under the guidance of the master Goto Magobei . Oe Masamichi also studied Eishin-ryu Bojutsu under the guidance of master Itagaki Taisuke. He inherited the leadership of Tanimura-ha, becoming her 17th soke . Oe Masamichi combined the directions of Tanimura-ha and Shimomura-ha, updating educational and technical programs . By the time of the global reform of the school, almost 160 techniques had accumulated  and reorganized them into Seiza (Shoden), Tachihiza (Chuden), Okuiai (Okuden) and Kumitachi waza, practiced today. Although he retained the original techniques, the names of some of them have been changed to help them understand them. Oe Masamichi renamed the reorganized Muso Jikiden school Eishin-ryu  in the Taisho era (1912 - 1926).

In 1900, Oe began teaching Kendo and Eishin-ryu in Kochi Prefecture at Dai Nippon Butokukai and in various local schools.  In 1924 he became the second person to be awarded the title of Hanshi in Dai Nippon Butokukai after Nakayama Hakudo.  Oe Masamichi died on April 18, 1927. Officially, Oe Masamichi did not leave a direct heir to the school, and about 20 of his closest students continued to spread Muso Jikiden Eishin-ryu outside the Tosa principality throughout Japan, founding several independent branches of the school (ha). Through the efforts of Oe Masamichi, iaido became an officially recognized art within the framework of traditional kobudo in 1932 after the death of 17 patriarchs. 60 years after the death of Oe Masamichi, a memorial stone was erected in his honor on Mount Godaysan.