As a practicing Zoroastrian, he dedicated much of his early life to studying to become a magus, after which he began travelling extensively throughout Western Asia to engage in constructive dialogue with non-Zoroastrian groups.

Prior to the Battle of the Trench in 627, Salman suggested to Muhammad and the other early Muslims that a large trench be dug around Yathrib (citing a technique commonly used by the Sasanian army) in order to help defend against the Quraysh, who were marching from Mecca in order to besiege the city.

[10][11][12] The first sixteen years of his life were devoted to studying to become a Zoroastrian magus or priest, after which he became the guardian of a fire temple.

[13] Salman traveled around the Middle East to discuss his ideas with priests, theologians and scholars in his quest for the truth, settling initially in Mosul (ancient Nineveh).

"[15] Salman came up with the idea of digging a great trench around the Medina, to defend the city against the army of 10,000 Arabian non-Muslims.

Muhammad and his companions accepted Salman's plan because it was safer, and there would be a better chance that the non-Muslim army would have a larger number of casualties.

"[17] Salman participated in the conquest of the Sasanian Empire, and became the first governor of Sasanid capital Ctesiphon, after its fall at the time of the second Rashidun Caliph, Umar ibn Al-Khattab.

[9] However, according to some other sources,[13] after Muhammad's death, he disappeared from public life until 656, when Ali became the Caliph, and appointed Salman as the governor of Al-Mada'in at the age of 88.

[4] Shi'ites, Twelvers in particular, hold Salman in high esteem for a hadith attributed to him, in which all twelve Imāms were mentioned to him by name, from Muhammad.

Ali Asgher Razwy, a 20th-century Shia Twelver Islamic scholar states: If anyone wishes to see the real spirit of Islam, he will find it, not in the deeds of the nouveaux riches of Medina, but in the life, character and deeds of such companions of the Apostle of God as Ali ibn Abi Talib, Salman el-Farsi, Abu Dharr el-Ghiffari, Ammar ibn Yasir, Owais Qarni and Bilal.

The orientalists will change their assessment of the spirit of Islam if they contemplate it in the austere, pure and sanctified lives of these latter companions.For Alawites, Salman is part of a divine trinity alongside Muhammad and Ali, the latter of whom is seen as a manifestation of Allah.

[27][28] In the Kitáb-i-Íqán, Bahá'u'lláh honours Salman for having been told about the coming of Muhammad: As to the signs of the invisible heaven, there appeared four men who successively announced unto the people the joyful tidings of the rise of that divine Luminary.