There are two major opinions on the matter. There is the Islamic Theological View and the Secular Historical View. The Islamic Theological Views will be presented first and the Secular Historical Views second, but this has no bearing on which one is correct. (That decision is up to the reader.)
Islamic Theological View
Answer 1: No Founder
Islam is not something to be founded or established. Islam is a God revelation to people and mankind through prophets and Messengers from Allah (or God in English); the almighty who created this universe and created mankind.
Islam is a religion. Islam is an Arabic word that means submission and surrender to God (as the one and only one God). In this sense Islam began by the universe creation where all God creatures were created under their submission (Islam) to God. Upon start of mankind, they are taught through God prophets to be on full submission (Islam) to God.
All prophet missions; including Noah, Abraham, Moses, Jesus, and Muhammad, was to hold submission (Islam) to the one and only one God, the Creator, with no partner, no son, no father, no companion, no associate, and no resemblance (defined as monotheism).
In this sense:
Islam religion per Qur'an revelation to prophet Muhammad began in year 610 AD by God revelation of first verses of Qur'an to prophet Muhammad through the angel Gabriel (Jibril). Prophet Muhammad (PBUH) was born in Makkah (or Mecca) and lived from approximately 570 AD to 632 AD. Prophet Muhammad (peace be upon him) is revered by Muslims but as a man, not as a God or son of God. Islam teaches that there is only One God, whom Muslims call "Allah" in Arabic (or God in English and same God worshiped in Judaism and Christianity).
Answer 2: Allah is the Founder
Islam religion is founded by Allah Himself. Allah tells in Quran that Islam has always been the right religion since the 1st human on Earth Adam and Eve (Peace be upon them). The last prophet sent from Allah was Muhammad (Peace be upon him). So he's the last prophet of Islam.
Mohammad was born in Mecca, the capital of Arabia, of mother Amina and father Abdullah, on the 20th August 570 A.D. His father died before his birth.
Answer 3: No Founder
Islam is not founded. Islam is a revelation from Allah "God" the almighty who created this universe and created mankind and knows exactly what he needs to be straighten.
Over the ages, Allah "God" the almighty, the Creator sent thousands of messengers to his creation "mankind" informing them of their Creator who should be worshiped alone and not to worship any of his creation like animals, trees, mountains, idols...etc.
People tend to either disbelieve these messengers and prophets or even kill them.
Adam hims self, peace be upon him all God's messengers, was a messenger to his sons.
Then Abraham, his sons too until Jesus who according the holy Qur'an and the old scripture told his followers the same message "to worship God alone" and that a last prophet "Mohammed of Islam" will come after him.
Islam came with the same message, but with broader boundaries, of the previous celestial religions from Adam to Christ, the ONENESS of God the Creator and no other gods are to be worshiped beside him.
The holy Qur'an of Islam is the true word of God which no man can every put one sentence like it. God used to send messengers with miracles which suit their time and environment. Moses time was famous of magicians, Christ has miracles such as bringing life to the dead, curing lepers...etc. and Mohammed's miracles were many including the Qur'an, language miracle as the Arabs were very strong in language and they poets... but Allah challenged them to make one sentence equal to the Qur'anic verses and they could not and will never do.
No human is responsible of founding, creating, or establishing Islam religion. Islam religion is God religion. Islam religion is per God (Allah) revelation of Qur'an to prophet Muhammad through the Angel Gabriel. Qur'an revelation started in year 610 AD and continued until year 632 AD (year of death of the prophet).
Islam religion, as defined above, should not be confused by Islam, as an Arabic word, that in its universal sense means peace and full submission to God (Allah), the one and only one God with no partner, no father, no son, no companion, and no resemblance. Islam in this sense is the main God mission to all prophets since start of mankind; including Noah, Abraham, Moses, Jesus, and Muhammad. However, Judaism and Christianity are the God religions per God revelation of , respectively, Torah and Bible to Moses and Jesus as well as the very name Islam is God religion per God revelation of Qur'an to prophet Muhammad.
Refer to related questions on why Qur'an was revealed and the golden rules in Qur'an.
Answer 4: Shiite View -- Allah is the Founder and Ahl al-Bayt is Protector
There is only one founder of Islam. Allah is the founder of Islam.
salaam of course Allah nominate Hazrat Muhammad (saws) as messenger of whole universe and to safe of Islam only the family of Hazrat Muhammad named imam Ali, Bibi Fatima ,Hassan and special imam Hussein in karbala.
Secular Historical Answer
Answer 1: Distinction between islam and Islam, which Mohammed Founded
For many Muslims the term "Islam" has two meanings: the Divine Religion of Submission to God's Will (often called Islam with a small "i") and the Institutionalized Belief as Found in Qur'an and Revealed by Muhammad's Prophecy (often called Islam with a capital "I").
islam with a small "i" is a concept that comes out of Islam with a capital "I" and projects the Established Religion of Islam back into the period before would have identified as Muslim. The purpose of said belief, in a functional sense, is to gird Islam in the history afforded by the Judeo-Christian prophetic lineage and ensure its authenticity. islam also affords the believer in Islam a continuity of tradition which Mohammed only continued and corrected as opposed to having the religion of Islam be an affront or disagreement with other divinely-inspired religions. Since islam is derivative of Islam, it does not actually exist prior to Islam.
Islam, as an Established Religion, was organized and directed by Mohammed, who was born in 570 C.E. at Mecca, in Saudi Arabia. According to Islam, he received revelations from God in Mecca in from the year 610-632 C.E. He was supported by several family members like his uncle Ali Ibn Talib and his first wife Khadija to pursue these prophecies. He converted other members to his nascent religion before being expelled from Mecca to Yethrib (now known as Medina) in 622 C.E. When Mohammed became the Chief Hakam or Judge/Administrator of Yethrib, he received many new revelations and began to ask members of his community to memorize these revelations (along with prior ones). These memorizers (in Arabic Hafeths) would eventually be responsible for the creation of one unified Qur'an. By Mohammed's death, he had conquered all of Arabia and converted most of Arabia to his new faith, establishing the grounds for an Islamic Caliphate, which succeeded him.
Answer 2: Mohammed Founded Islam
Islam was founded by an illiterate trade merchant named Muhammad ibn Abdallah. Until approximately 25 years of age he was Pagan, like his parents and grandparents. He never worshiped an idol. Then in the cave of Hira he was approached by angel. He was scared . however, his wife Khadija convinced him he was approached by an angel who ordered him to recite the first verses of the new religion. The new religion is called "Islam" that means "submission". this means submission to Allah (or God and same God worshiped in Judaism and Christianity).
However, after trying to spread this new religion in his home town of Makkah (or Mecca), Muhammad found that 10 years later his followers could be counted by the fingers of two hands. This did not satisfy his ambitions and he fled to Medina and started to rob caravans from Mecca. These raids quickly brought him enough money to recruit new followers with whom he started to raid other tribes subduing them and making them his allies.
Very soon his wealth grew as well as the number of his followers, and then he started the expansion on other lands. This process was followed by his companions after his death and in less than 150 years, Muslims subdued and made islamic the vast territories from Arabia, through Egypt and Palestine to the North Africa and then to Europe in the North to Persia and India in the East.
Additional Comments on the Secular Historical View from the proponents of the Islamic Theological View
It was revealed from God to Prophet Muhammad (peace and blessings of God be upon him)
The founder of Islam was Prophet Muhammad (P.). Born in 570 A.D., Ubu'l Kassim founded Islam in 610 A.D. and then changed his name to Muhammad.
Islam teaches that all of God's prophets, from Adam to Muhammad, God bless them and grant him peace, were prophets of Islam. The modern Islamic movement began in Makkah in the 7th century A.D., and was started by Prophet Muhammad, God bless him and grant him peace. Islam teaches that all of God's prophets, from Adam to Muhammad, God bless them and grant him peace, were prophets of Islam. The modern Islamic movement began in Makkah in the 7th century A.D., and was started by Prophet Muhammad, God bless him and grant him peace. Muhammed (s.a.w) let peace be upon him.
Muḥammad bin Abdullah (the son of Abdullah), was the founder of Islam.
Founder of Islam is Allah (The God ).
The prophet Muhammad is often regarded as the founder of Islam.
There is no Patriarch for Islam. Allah (or God in English) is the founder for Islam. Refer to related question below.
Another answer from our community:Allah (God in English) is the founder of Islam. Allah is everywhere every time.
No Allah (God in English) is the Islam founder. Refer to related question below.
Nobody ate Muhammad (the founder of Islam). He was buried in a grave and left untouched.
yes, Allah (or God in English) is the founder of Islam. Refer to related question below.
The prophet Mohammad was the founder of Islam.
The founder of Islam is Allah (God in English). Islam dates back to start of universe creation. Refer to related question below.
Another answer from our community:No man founded Islam. Allah (God in English) is the Islam founder. Refer to related question below.
Muhammad was the founder of Islam and the proclaimer of the Qurʾān, Islam's sacred scripture.
The founder of Islam is Allah (God in English). Muhammad is the prophet of Islam per Quran God revelation to him. He was born in year 570 AD.