Ghalib started composing poetry at the age of 11. His first language was Urdu, but Persian and Turkish were also spoken at home. He got his education in Persian and Arabic at a young age. When Ghalib was in his early teens, a newly converted Muslim tourist from Iran (Abdus Samad, originally named Hormuzd, a Zoroastrian) came to Agra. He stayed at Ghalib's home for 2 years. He was a highly educated individual and Ghalib learned Persian, Arabic, philosophy, and logic from him.

Although Ghalib himself was far prouder of his poetic achievements in Persian, he is today more famous for his Urdu ghazals. Numerous elucidations of Ghalib's ghazal compilations have been written by Urdu scholars. The first such elucidation or Sharh was written by Ali Haider Nazm Tabatabai of Hyderabad during the rule of the last Nizam of Hyderabad. Before Ghalib, the ghazal was primarily an expression of anguished love; but Ghalib expressed philosophy, the travails and mysteries of life and wrote ghazals on many other subjects, vastly expanding the scope of the ghazal. This work is considered his paramount contribution to Urdu poetry and literature.

In keeping with the conventions of the classical ghazal, in most of Ghalib's verses, the identity and the gender of the beloved is indeterminate. The critic / poet / writer Shamsur Rahman Faruqui explains that the convention of having the "idea" of a lover or beloved instead of an actual lover / beloved freed the poet - protagonist - lover from the demands of realism. Love poetry in Urdu from the last quarter of the seventeenth century onwards consists mostly of "poems about love" and not "love poems" in the Western sense of the term.

The first complete English translation of Ghalib's ghazals was written by Sarfaraz K. Niazi and published by Rupa & Co in India and Ferozsons in Pakistan. The title of this book is Love Sonnets of Ghalib and it contains complete Roman transliteration, explication and an extensive lexicon.

Mirza Ghalib was a gifted letter writer. Not only Urdu poetry but the prose is also indebted to Mirza Ghalib. His letters gave foundation to easy and popular Urdu. Before Ghalib, letter writing in Urdu was highly ornamental. He made his letters "talk" by using words and sentences as if he were conversing with the reader. According to him "sau kos se ba-zaban-e-qalam baatein kiya karo aur hijr mein visaal ke maze liya karo" [from hundred of miles talk with the tongue of the pen and enjoy the joy of meeting even when you are separated]. His letters were very informal, some times he would just write the name of the person and start the letter. He himself was very humorous and also made his letter very interesting. He said "main koshish karta hoon keh koi aisi baat likhoon jo parhay khoosh ho jaaye" [I want to write the lines that whoever reads those should enjoy it]. Some scholar says that Ghalib would have the same place in Urdu literature if only on the basis of his letters.They have been translated into English by Ralph Russell, The Oxford Ghalib.

Ghalib was a chronicler of this turbulent period. One by one, Ghalib saw the bazaars – Khas Bazaar, Urdu Bazaar, Kharam-ka Bazaar, disappear, whole mohallas (localities) and katras (lanes) vanish. The havelis (mansions) of his friends were razed to the ground. Ghalib wrote that Delhi had become a desert. Water was scarce. Delhi was now “a military camp”. It was the end of the feudal elite to which Ghalib had belonged. He wrote:

“An ocean of blood churns around me -
Alas! Were these all!
The future will show
What more remains for me to see”.

His original Takhallus (pen name) was Asad, drawn from his given name, Asadullah Khan. At some point early in his poetic career he also decided to adopt the takhallus 'Ghalib' (meaning all conquering, superior, most excellent). Popular legend has it that he changed his pen name to 'Ghalib' when he came across a sher (couplet) by another poet who used the takhallus (pen name) 'Asad'. The legend says that upon hearing the couplet, Ghalib ruefully exclaimed, "whoever authored this couplet does indeed deserve the Lord's rahmat (mercy) (for having composed such a deplorable specimen of Urdu poetry). If I use the takhallus Asad, then surely (people will mistake this couplet to be mine and) there will be much la'anat (curse) on me!" And, saying so, he changed his takhallus to 'Ghalib'. However, this legend is little more than a figment of the legend's creator's imagination. Extensive research performed by commentators and scholars of Ghalib's works, notably Imtiyaz Ali Arshi and Kalidas Gupta Raza, has succeeded in identifying the chronology of Ghalib's published work (sometimes down to the exact calendar day!). Although the takhallus 'Asad' appears more infrequently in Ghalib's work than 'Ghalib', it appears that he did use both his noms de plume interchangeably throughout his career and did not seem to prefer either one over the other.

In 1855, Sir Syed Ahmed Khan finished his highly scholarly, very well researched and illustrated edition of Abul Fazl’s Ai’n-e Akbari, itself an extraordinarily difficult book. Having finished the work to his satisfaction, and believing that Mirza Asadullah Khan Ghalib was a person who would appreciate his labours, Syed Ahmad approached the great Ghalib to write a taqriz (in the convention of the times, a laudatory foreword) for it. Ghalib obliged, but what he did produce was a short Persian poem castigating the Ai’n-e Akbari, and by implication, the imperial, sumptuous, literate and learned Mughal culture of which it was a product. The least that could be said against it was that the book had little value even as an antique document. Ghalib practically reprimanded Syed Ahmad Khan for wasting his talents and time on dead things. Worse, he praised the “sahibs of England” who at that time held all the keys to all the a’ins in this world.

This poem is often referred to but has never been translated in English. Shamsur Rahman Faruqi wrote an English translation. The translation is accurate if lacking the felicity of the original:

The poem was unexpected, but it came at the time when Syed Ahmad Khan’s thought and feelings themselves were inclining toward change. Ghalib seemed to be acutely aware of a European [English] sponsored change in world polity, especially Indian polity. Syed Ahmad might well have been piqued at Ghalib’s admonitions, but he would also have realized that Ghalib’s reading of the situation, though not nuanced enough, was basically accurate. Syed Ahmad Khan may also have felt that he, being better informed about the English and the outside world, should have himself seen the change that now seemed to be just round the corner. Sir Syed Ahmad Khan never again wrote a word in praise of the Ai’n-e Akbari and in fact gave up taking active interest in history and archealogy, and became a social reformer.

Mirza was born in Kala Mahal in Agra. In the end of 18th century, his birthplace was converted into Indrabhan Girls' Inter College. The birth room of Mirza Ghalib is preserved within the school. Around 1810, he was married to Umrao Begum, daughter of Nawab Ilahi Bakhsh Khan of Loharu (younger brother of the first Nawab of Loharu, Nawab Mirza Ahmad Baksh Khan, at the age of thirteen. He had seven children, none of whom survived (this pain has found its echo in some of Ghalib's ghazals). There are conflicting reports regarding his relationship with his wife. She was considered to be pious, conservative and God fearing.

Ghalib was proud of his reputation as a rake. He was once imprisoned for gambling and subsequently relished the affair with pride. In the Mughal court circles, he even acquired a reputation as a "ladies man". Once, when someone praised the poetry of the pious Sheikh Sahbai in his presence, Ghalib immediately retorted:

He died in Delhi on February 15, 1869. The house where he lived in Gali Qasim Jaan, Ballimaran, Chandni Chowk, in Old Delhi has now been turned into 'Ghalib Memorial' and houses a permanent Ghalib exhibition.

Ghalib was a very liberal mystic who believed that the search for God within liberated the seeker from the narrowly Orthodox Islam, encouraging the devotee to look beyond the letter of the law to its narrow essence. His Sufi views and mysticism is greatly reflected in his poems and ghazals. As he once stated:

Like many other Urdu poets, Ghalib was capable of writing profoundly religious poetry, yet was skeptical about the literalist interpretation of the Islamic scriptures. On the Islamic view and claims of paradise, he once wrote in a letter to a friend:

He staunchly disdained the Orthodox Muslim Sheikhs of the Ulema, who in his poems always represent narrow mindedness and hypocrisy:

In another verse directed towards the Muslim maulavis (clerics), he criticized them for their ignorance and arrogant certitude: "Look deeper, it is you alone who cannot hear the music of his secrets". In his letters, Ghalib frequently contrasted the narrow legalism of the Ulema with "it's pre-occupation with teaching the baniyas and the brats, and wallowing in the problems of menstruation and menstrual bleeding" and real spirituality for which you had to "study the works of the mystics and take into one's heart the essential truth of God's reality and his expression in all things".

He believed that if God laid within and could be reached less by ritual than by love, then he was as accessible to Hindus as to Muslims. As a testament to this, he would later playfully write in a letter that during a trip to Benares, he was half tempted to settle down there for good and that he wished he had renounced Islam, put a Hindu sectarian mark on his forehead, tied a sectarian thread around his waist and seated himself on the banks of the Ganges so that he could wash the contamination of his existence away from himself and like a drop be one with the river.

In his poem "Chirag-i-Dair" (Temple lamps) which was composed during his trip to Benaras during the spring of 1827, Ghalib mused about the land of Hindustan (the Indian subcontinent) and how Qiyamah (Doomsday) has failed to arrive, in spite of the numerous conflicts plaguing it.

Indian Cinema has paid a tribute to the legendary poet through a film (in sepia / black and white) named Mirza Ghalib (1954) in which Bharat Bhushan plays Ghalib and Suraiya plays his courtesan lover, Chaudvin. The musical score of the film was composed by Ghulam Mohammed and his compositions of Ghalib's famous ghazals are likely to remain everlasting favorites.

Pakistani Cinema has also paid tribute to the legendary poet through another film also named Mirza Ghalib. The film was directed by M.M. Billoo Mehra and produced as well by M.M. Billoo Mehra for S.K. Pictures. The music was composed by Tassaduq Hussain. The film starred Pakistani film superstar Sudhir playing Ghalib and Madam Noor Jehan playing his courtesan lover, Chaudvin. The film was released on November 24, 1961 and reached average status at the box office, however, the music remains memorable in Pakistan to this day.

Gulzar produced a TV serial, Mirza Ghalib (1988), telecast on DD National that was immensely successful in India. Naseeruddin Shah played the role of Ghalib in the serial, and it featured ghazals sung and composed by Jagjit Singh and Chitra Singh. The serial's music has since been recognised as Jagjit Singh and Chitra Singh's magnum opus enjoying a cult following in the Indian subcontinent.

The Pakistan government in 1969 commissioned Khaliq Ibrahim (died 2006) to make a documentary on Mirza Ghalib. The movie was completed in 1971 - 72. It is said, that the movie, a docudrama, was historically more correct than what the official Pakistan government point of view was. Thus, it was never released. Till this date, barring a few private viewings, the movie is lying with the Department of Films and Publication, Government of Pakistan. The movie was made on 16 mm format. Ghalib's role was played by actor Subhani Bayunus, who later played this role in many TV productions.

Various theatre groups have staged plays related to the life of Mirza Ghalib. These have shown different lifestyles and the way he lived his life. Qaid-e-Hayat (Imprisonment of Life, 1983) written by Surendra Verma talks about the personal life of poet Ghalib, including his financial hardships and his tragic love for Katiba, a woman calligraphist, who was working on his diwan. Over the years, it has been directed by numerous theatre directors, including Ram Gopal Bajaj in 1989, at the National School of Drama, Delhi.

An animation film on Mirza Ghalib is telecast on Zee Cinema.

Ghalib is still very popular today, and his poetry is well known. Ghazal singer Jagjit Singh had sung some of his most beautiful ghazals.