Henry Carey was born in London and The Gentleman's Magazine said in 1795 that he was the illegitimate son of George Savile, 1st Marquess of Halifax. Carey did not make the claim himself, but he did use "Savile" as the name of three of his male children, and these corresponded to the births of Halifax's own three sons. Furthermore, he dedicated all of his major works to Halifax (Gillespie 127). His biography in The Gentleman's Magazine also stated that Carey received a "generous annuity" from the Savile family, but that seems less likely and remains unconfirmed. The fact that, even when his most popular plays were on the boards, Carey would write for pay argues against such an annuity.

Aside from rumor, it is impossible to be sure of Carey's parents. It is possible that a Henry and a Mary Carey, both school teachers, were his parents. Indeed his first profession, according to Richard Hawkins, was as a music teacher in a boarding school for the middle gentry, a position he held while also working as an author, so these two Careys are the most likely candidates for at least his surrogate, if not his biological, parents.

Scholars have trouble identifying Carey's first works, because he was probably writing anonymously. According to Laetitia Pilkington, friend of Jonathan Swift's and other Tory wits, Carey worked as a "subaltern" to James Worsdale later in his life, in 1734, when he was best paid and most famous. Since he was writing for pay when he had theatrical successes, it seems reasonable that he had been hiring his pen for quite some time. In the 18th century, he appears to have done hack work for the periodicals of the day. His first accredited work was a weekly publication of a set of serialized romance fictions entitled Records of Love in January through March of 1710. This work was aimed at a female readership and was written with a clear expectation of an intelligent, educated, and populous set of readers. He also appears as a singer of Italian and English entre-acte songs at Theatre Royal, Drury Lane around 1710 (Gillespie 127). His first poetry publication came in 1713, the year of the height of the Tory ministry under Queen Anne with Poems on Several Occasions.

In 1714, Carey had a job as a psalmist at Lincoln's Inn church and also at Drury Lane. He performed there with his music students. Critically, the Tory ministry fell with the death of Anne, and Robert Walpole's Whigs were on the rise. The leaders of the former government, Robert Harley and Henry St. John, were accused of treason over the coming months, and, while St. John fled, Harley was imprisoned in the Tower of London. In 1715, Carey wrote his first play, an afterpiece entitled The Contrivances. On July 13, 1717, Carey lost both of his jobs, at Drury Lane and at Lincoln's Inn, for a singular political statement. Harley had just been freed from the Tower and had attended Lincoln's Inn Church, and Carey set Psalm 124 to a jaunty, celebratory tune and sang it. The Psalm concerns the Exodus of the Israelites, announcing that

"If it had not been the Lord who was on our side, when men rose up against us:

Then they had swallowed us up quick, when their wrath was kindled against us:

Then the waters had overwhelmed us, the stream had gone over our soul."

It concludes with "Our soul is escaped as a bird out of the snare of the fowlers: the snare is broken, and we are escaped."

Even though Carey lost those two jobs, he was soon back at Drury Lane, and he married Elizabeth Pearks in September. He produced his second play, Hanging and Marriage, in 1722. The theatrical seasons of 1723 and 1724 were dominated by pantomime and spectacle plays in London (inducing a young William Hogarth to satirize the abandonment of drama for puppets), and Carey worked providing the music to some of these productions. In 1723, he wrote the music for Harlequin Dr. Faustus (text, such as it was, by Barton Booth) at Drury Lane. From 1723-1733, Carey was the "unofficial composer in residence" for Drury Lane, and he wrote and performed much of the music between acts, preludes, and epilogue music, as well as the music called for by dances and other entertainments in the plays (Gillespie 127).

Henry Carey never ceased to be a composer nor to work as a singer and musician. Even as he began to have greater success as a poet and playwright, he continued to work in music. Furthermore, Carey worked in a theatre that was associated with the Whig party. Colley Cibber, Robert Wilks, and Barton Booth were patronized first by Joseph Addison and his circle and then by Robert Walpole and his circle, and yet Carey appears to have been an unambiguous supporter of the Tory ministry of Henry St. John and Harley and the literary circle of Alexander Pope. When, therefore, Pope satirized the theatrical vacuity of the pantomime stage in The Dunciad, he was aiming not at the musicians and composers, but rather at the replacement of drama with spectacle.

His poem, Namby Pamby (1725), satirized Ambrose Philips who was a frequent and famous target of Alexander Pope's wrath. Philips had written a series of odes to "all persons", from Robert Walpole to the mother in the nursery, and the latter provided the occasion for Carey to exaggerate. Philips had employed a 2.5' iambic line, and Carey devastatingly claimed that the half-line matched Philips's halfwitted conception. The poem was so successful that Carey himself began to be known as "Namby Pamby Carey" (while Philips became known as "Namby Pamby"), and the poem even came to be used as children's literature. Furthermore, the term "namby pamby" came into widespread usage to describe any nonsensical frippery. "Sally in Our Alley", one of Carey's songs, was also exceptionally successful, and it has been performed by many singers through to the modern era.

Carey was, after Namby Pamby, a well known figure among those opposed to Robert Walpole, and the poem had been praised by Alexander Pope (as "Sally in our Alley" had been by Joseph Addison). Carey was an admirer and subscriber to the operas of Handel, but he, like John Gay and Alexander Pope, thought that the operatic stars were absurd. Therefore, he began to satirize opera in 1726 and in that year he produced Faustina, or, the Roman Songstress, a satire of Faustina Bordoni. Faustina was at that time in a hissing fight with Francesca Cuzzoni and actually came to blows the next year during a performance of Handel. In the next year, he wrote Mocking is Catching to satirize Senesino, the Italian castrati opera star.

In 1730, Carey may have been the first to sing "God Save the King" at a Patriot Whig meeting, and there is some reason to attribute the song to him. Also that year, he added music and introduced ballads for his previous play, Hanging and Marriage, and put the play on as The Clown's Stratagem. He used the basic text of the play again, with new music, for Betty, or, The Country Bumpkins in 1732. These two characteristics...a love of opera and frustration at its abuses and a love of patriotism and frustration at Walpole's policies...would show up in all of Carey's professional works.

As a playwright, Carey was a significant figure in the re-emergence of satirical drama in the 1730s. After the success of Namby Pamby, Carey was favored by the older generation of Tory wits and the Scriblerus Club. After John Gay's invention of the ballad opera with The Beggar's Opera, Carey turned to writing musical burlesques. He wrote a great deal of music and some librettos for other playwrights during this period.

In 1732, J. F. Lampe, Thomas Arne, J. C. Smith and Henry Carey formed the English Opera project. Their goal was to revive serious opera in English. Together, they formed the English Opera Company, and Carey wrote two librettos, for Amelia (set by Lampe and acted at the Little Theatre at The Haymarket (an opposition playhouse favored by Henry Fielding)) and Teraminta (set by Smith and performed at Lincoln's Inn Fields). Amelia was a great popular success, but the opera company failed, and the project came to nought (Gillespie 128).

Having satirized the foreignness of opera, in 1734 Carey turned his attention to the poorly written, mass produced tragedy. Chrononhotonthologos was a parody of bombastic tragedy and, particularly, the very hack-written spectacle plays he had collaborated on at Drury Lane. The play was daring, for it was a satire of Caroline of Ansbach and George II of the United Kingdom. The Queen was attacked for her alliance with Robert Walpole and her general caprice. It also had a generous amount of music by Carey. If contemporary allies understood the criticisms inherent in the play, it was also possible to see it as a burlesque with nonsense verse. He followed that up with the ballad farce of The Honest Yorkshire-Man.

Interestingly, although Carey's attempt to revive serious, patriotic English opera did not work, his attempts at parody and satire in opera did. He had previously satirized the exoticism and emptiness of the English public's love of prima donna singers and castrati, but in 1737, he adapted The Dragon of Wantley from a Lincolnshire folk ballad into a full mock-opera. This literary adaptation was a step beyond adapting literary plays into ballads (as John Gay had done), for it began with a folk ballad and transformed it into opera. The play, with music by John Frederick Lampe, punctured the vacuous operatic conventions and pointed a satirical barb at Robert Walpole and his taxation policies. The play was a huge success. Its initial run was sixty-nine performances in the first season, which exceeded even The Beggar's Opera. The play debuted at the Haymarket, where its coded attack on Walpole would have been clear, but its long run occurred after it moved to Covent Garden, which had a much greater capacity for staging. Part of its satire of opera was that it had all of the words sung, including the recitatives and da capo arias (Gillespie 128). The play itself is very brief on the page, as it relied extensively on absurd theatrics, dances, and other non-textual entertainments. The Musical Entertainer from 1739 contains engravings showing how the staging was performed (Gillespie 128).

From 1737 to 1740, he wrote The Musical Century in one Hundred English Ballads in two volumes. Although Carey complained that his enemies were calling him "Ballad-maker," the work was praised later by Charles Burney, and in the 19th century opinion of Carey's clear, simple, and memorable ballad tunes went even higher. Also in 1738, he helped found the Fund for Decayed Musicians, and he produced Margery, or, a Worse Plague than the Dragon, a sequel to The Dragon of Wantley.

He had another popular success in 1739 with Nancy, or, The Parting Lovers, a patriotic play about a sailor leaving his beloved to fight against the Spanish. As with other works, Carey's point was primarily patriotic. Patriotic plays at the time were often demurrals of official policy and England's foreign entanglements. Nancy was set as well as written by Carey, and its main characters are a sailor, Nancy, and a Press Gang officer. The play broke new ground in explicitly treating a contemporary matter of social concern in song (Gillespie 128).

Carey's son, Charles, died in 1743, and Carey hanged himself at his home in London later that year.

While the anonymous account in The Gentleman's Magazine says that Carey had an annuity, he left a pregnant second wife (Sarah, whom he married between 1729 and 1733) and three dependent children, and both Hawkins and The London Stage say that he was despondent over financial difficulties. Grief over the death of his son is another possible explanation of his suicide, and Suzanne Aspden speculates that Carey suffered from paranoia, while others have suspected that he had depression or other maladies. His daughter Anne would become an actress and bear an illegitimate son, Edmund Carey, who would later be known as Edmund Kean.

Henry Carey's work has been tarred with allegations of triviality since his own day. He had an extraordinary gift with melody and wordplay, and later authors, such as Edward Lear, would cite Carey as a predecessor for his tongue twisters and nonsense verse in Namby Pamby and Chrononhotonthologos. At the same time, Carey's productions were noted in his own day for their political acuity and bravery (if not foolhardiness). He was willing to offend and suffer the consequences of his convictions, but he made his political statements in a diverting and apparently frivolous manner, thereby allowing his friends to respond to his politics and his enemies to dismiss his levity. In the Macaulay-dominated view of literary history of the early 20th-century, Carey was represented as a balladeer whose fundamental moroseness was proven by his shameful suicide, and his plays, now devoid of topicality, were set as broad entertainments.

Musicologists have recognized, however, the subtle gifts necessary for Carey's music, and theater historians are beginning to recognize the context of his plays. He was the most prolific English song composer of 1715-1740, and he wrote his own lyrics to all but twelve of his two hundred and fifty songs (Gillespie 128). He was responsible for linking the vocal style of Henry Purcell to the later style of Arne by combining popular English folks song and tavern song with Italian flourishes.