The following is a summary of the biblical Book of Daniel

In the third year of the reign of Jehoiakim (BC 606), Daniel and his friends Hananiah, Mishael, and Azariah were among the young Jewish nobility carried off to Babylon. The four were chosen for their intellect and beauty to be trained as advisors to the Babylonian court,() Daniel was given the name Belteshazzar, i.e., prince of Bel, or Bel protect the king!(not to be confused with the neo-Babylonian king, Belshazzar). Hananiah, Mishael, and Azariah were given the Babylonian names, Shadrach, Meshach, and Abednego, respectively. At the close of his three years of discipline and training in the royal schools Daniel was brought out into public life. He soon became known for his skill in the interpretation of dreams (; ). Daniel made known and interpreted Nebuchadnezzar's dream; as well as a later dream preceding the king's descent into animal behaviour, and many years afterwards, when he was now an old man, amid the alarm and consternation of the terrible night of Belshazzar's impious feast (in which Belshazzar and his concubines drank wine out of the royal Jewish ceremonial goblets of the Temple), Daniel was called in at the suggestion of the queen-mother to interpret the mysterious handwriting on the wall. For successfully reading the cryptic handwriting by an angel of God, Daniel was rewarded by the Babylonians with a purple robe and elevation to the rank of "third ruler" of the kingdom. It is believed that the place of "second ruler" was held by Belshazzar as associated with his father, Nabonidus, on the throne (), though no where in the book of Daniel is Nabonidus mentioned by name and according to the book of Daniel Nebuchadnezzar was the father of Belshazzar. Nabonidus left Babylon in his son Belshazzar's care when he fled because of his refusal to accept the role of Marduk as the prime diety. The Hebrew word translated in the book of Daniel as "son" can mean any descendant. Belshazzar was actually the grandson of Nebuchadnezzar. Daniel interpreted the handwriting, and "in that night was Belshazzar the king of the Chaldeans slain".

After the Persian conquest of Babylon, Daniel held the office of the first of the "three presidents" of the empire under the reign of Darius the Mede, and was thus practically at the head of state affairs, with the ability to influence the prospects of the captive Jews (), whom he had at last the happiness of seeing restored to their own land; although he did not return with them, but remained still in Babylon.

Daniel's fidelity to God exposed him to persecution by jealous rivals within the king's administration. The fact that he had just interpreted the emperors' dream had resulted in his promotion and that of his companions. Being favored by the King, Cyrus the Great, he was untouchable. His companions were vulnerable to the accusation that had them thrown into the furnace for refusing to worship the Babylonian King, Nebuchadnezzar as a god; but they were miraculously saved, and Daniel would years later be cast into a den of lions (for continuing to practice his faith in YHWH), but was miraculously delivered; after which Cyrus issued a decree enjoining reverence for "the God of Daniel" (). He "prospered in the reign of Darius, and in the reign of Cyrus the Great," whom he probably greatly influenced in the matter of the decree which put an end to the Jewish Captivity (BC 536).

Daniel's ministry as a prophet began late in life. Whereas his early exploits were a matter of common knowledge within his community, these same events, with his pious reputation, serve as the basis for his prophetic ministry. The recognition for his prophetic message is that of other prophets like Isaiah, Jeremiah and Ezekiel whose backgrounds are the basis for their revelations.

The time and circumstances of Daniel's death have not been recorded. However, tradition maintains that Daniel was still alive in the third year of Cyrus according to the Tanakh (). He would have been almost 100 years old at that point, having been brought to Babylon when he was in his teens, more than 80 years previously. Many posit that he possibly died at Susa in Iran. Tradition holds that his tomb is located in Susa at a site known as Shush-e Daniyal. Other locations have been claimed as the site of his burial, including Daniel's Tomb in Kirkuk, Iraq, as well as Babylon, Egypt, Tarsus and, notably, Samarkand, which claims a tomb of Daniel (see "The Ruins of Afrasiab" in the Samarkand article), with some traditions suggesting that his remains were removed, perhaps by Tamerlane, from Susa to Samarkand (see, for instance, Itinerary of Benjamin of Tudela, section 153).

From Chapter 7 to the end of the book of Daniel, an apocalyptic vision is being described, supposedly from the perspective of Daniel. This marks a change in the narrative from Daniel interpreting to messengers of God interpreting for Daniel. Daniel dreams of four beasts that come out of the sea: a lion with eagles wings, a bear with three tusks, a leopard with four wings and four heads, and a beast with iron teeth, ten horns and one little horn and human eyes.() These beasts are all present at a convening of the divine counsel. Presiding over the counsel is the Ancient of Days, which may, in fact, be the Israelite God. The Ancient One proceeds to put to death the beast with the one little horn. () Daniel also describes the fates of the other beasts saying that while their dominion was taken away, their lives were prolonged. () This introduction leads into a series of dreams and visions where these events are expressed in greater detail.

Scholars argue that each of these beasts represents an emperor or kingdom that ruled over the Israelites. The first being Babylon, then Media, then Persia, and finally the Greeks. The horns of the last beast may be symbolic of the rulers that replaced Alexander the Great upon his death, culminating with the little horn, or Antiochus IV. There are additional details in the text that allude to Antiochus IV, including some form of desecration to the temple () and persecution (). The final message of the second half of Daniel is that God will deliver the people from oppression, the latest of which is Antiochus IV.

The prophet Ezekiel, with whom Daniel was a contemporary, describes a Daniel as a "pattern of righteousness (14:14, 20) and wisdom" (28:3). In the Book of Daniel, the name is spelled with a middle letter suggesting the i of that name ... but this letter is not included in Ezekiel, suggesting that the reference there may be to another person, possibly the "Danel" ("Judgement of God") known from Caananite Ugaritic literature (such as the Epic of Aqhat and Anat), whose reputation for wisdom and righteousness had made him legendary. (Vowel-points were not added to the consonantal Hebrew text before well into the Common Era, and the scribes may then have slipped in a vowel-point for "i" as a middle syllable.)

In the Deuterocanonical portion of Daniel known as Bel and the Dragon, the prophet Habakkuk is miraculously transported by an angel to take a meal to Daniel while he is in the lions' den. In response, Daniel prays, "Thou hast remembered me, O God; neither hast thou forsaken them that seek Thee and love Thee".

There are six different locations claiming to be the site of the tomb of the biblical figure Daniel: Babylon, Kirkuk and Muqdadiyah in Iraq, Susa and Malamir in Iran, and Samarkand in Uzbekistan.

On the Eastern Orthodox liturgical calendar, the feast days celebrating St. Daniel the Prophet together with the Three Young Men, falls on December 17 (during the Nativity Fast), on the Sunday of the Holy Forefathers (the Sunday which falls between 11 and 17 December), and on the Sunday before Nativity. Daniel's prophesy regarding the stone which smashed the idol () is often used in Orthodox hymns as a metaphor for the Incarnation: the "stone cut out" being symbolic of the Logos (Christ), and the fact that it was cut "without hands" being symbolic of the virgin birth. Thus the hymns will refer to the Theotokos (Virgin Mary) as the "uncut mountain"

In the West, the Roman Catholic Church commemorates Daniel on July 21.

He is commemorated as a prophet in the Calendar of Saints of the Lutheran Church - Missouri Synod together with the Three Young Men (Shadrach, Meshach, and Abednego), on December 17. Today in History - December 17

He is commemorated as a prophet in the Coptic Church on the 23rd day of the Coptic month of Baramhat.

Daniel is a very common and popular name nowadays in a variety of countries, notably those with a Judeo-Christian heritage. Usually used as a first name, it is followed by a last name.

Muslims traditionally consider Daniel (Arabic: ??????, Danyal) as an Islamic prophet, alongside the other major prophets of the Old Testament, namely Isaiah, Jeremiah and Ezekiel. Although he is not mentioned in the Qur'an, there are a few Hadith which bear his name and which refer to his time spent in the den of the lions. There are debates, however, that go on about Daniel's time of preaching and some Muslims believe that he was not a prophet but a saintly man.