THE VAGARIES OF Thomas Moore's reputation, as Ronan Kelly points out, could form a book in themselves. After precocious and scandalous success with barely anonymous erotic lyrics in the first years of the 19th century, his user-friendly Irish Melodies set an enduring stamp on the romantic image of Ireland for the Victorian age.

Charming and charismatic, his own performances of these yearning songs about love and country created a furore, and his spectacular social life, as an intimate of the Prince Regent's circle and then one of Byron's closest friends, earned him celebrity status. Therefore the cultural and nationalist revivalists at the end of the 19th century viewed him with suspicion, and to Yeats he represented bygone prettiness, easy sentimentality and political collaboration.

For some years now this image has been readjusted, helped by large-scale scholarly editions of his letters and journals, rescuing them from bowdlerisation. Kelly's interest in Moore began with his political writings, which do not fit the dismissive stereotype at all, and this new biography is an enthusiastic, persuasive and highly readable attempt to restore a full picture of the man. Kelly also follows recent scholarship in seeing works such as the wildly successful but now unreadable Lalla Rookh and The Fire-Worshippers as pioneering efforts at allegorising Irish issues through an Orientalized lens.

Above all Bard of Erin is a vividly absorbing picture of cross-cultural traffic across the Irish Sea in the early years of the Union. A Catholic grocer's son, Moore was not alone in setting out to “conquer England”, in Bernard Shaw's phrase, by means of poetry, music and journalism; he was part of a talented migration of Irish artists and writers who colonised the metropolis, to the loss of the decaying Irish capital they left behind them. No wonder that the Melodies are stamped with regret and nostalgia.

But Moore was also a realist, and Kelly shows that his commitment to Catholic civil rights (indefensibly withheld at the time of the Union, and granted only under duress nearly 30 years later) remained the touchstone of his political credo.

His nationalist credentials are more difficult to trace, but the martyrological bent of his national songs, and his respect for his revolutionary friends Robert Emmet and Lord Edward Fitzgerald, stamp his writings.

So does his powerful sense of the oppressive conditions of the Irish peasantry, immortalised in his angry satire Memoirs of Captain Rock. For all his stratospheric social connections, he was consistent in the things that mattered and remained devotedly close to his parents.

Survival and success required keeping a foot on either side of the Irish Sea: if Ireland was his subject, England was his bread and butter. Kelly shows Moore's attempted manipulation of patronage networks, which sometimes backfired disastrously (his middle years were ruined by a huge debt incurred when he delegated a supposed plum job he had landed in Bermuda). His early friendship with the Regent turned sour when the Prince's true views on Catholic Emancipation became clear, and Moore made him the butt of scathing political “squibs”.

Even at the height of his success Moore preferred to live in rented country cottages with his adored wife (who disliked high society), and to ration his London appearances carefully. In any case, his literary friends meant most to him.

Though his relationship with Shelley never proceeded beyond mutual caution, he became close to Scott, and particularly to Byron, who told him that they were “embarked in the same Ship of Fools together” and teasingly advised him “not to be so damned poetical”.

The bitchy Leigh Hunt's supposed quotation from Byron himself, that “Tommy dearly loved a Lord”, should be discounted. They certainly loved each other; the friendship begun, in classical style, with a challenge to a duel ended only in Byron's death. Moore - then living outside Britain under duress of debt - had visited him in Venice and was given the manuscript of Byron's legendary memoirs, a damnosa hereditas if ever there was one. The afterlife of this incendiary material, smouldering away in London after Byron's premature death and tussled over by rival lovers, family members, publishers and friends before its formal burning, is treated as dramatically as it deserves. Moore's position was impossible, and his behaviour - in the end - self-sacrificing. His eventual biography of Byron was an important work, but written under strictures that he had brought upon himself. And instead of bringing him money, it actually embedded Moore even further in debt.

Counterpointed against public success were financial worry and family tragedy. Running debts pursued him, not entirely because of his own extravagance, and his two sons cost him dear - before they, like their three sisters, predeceased him. Despite the pathos and diminuendo of his last years, his fame was assured.

The catchphrases created by the allusive and evocative Melodies are woven through Joyce's fiction, and the songs themselves lived on in drawing rooms up to the early 20th century, given an extra punch by John McCormack's marvellous recordings. But the variety, experimentalism and contemporary effect of his other writings are still up for rediscovery. Byron's advice was taken: everything in this eloquent and intelligent life shows that Moore's achievement decisively transcended the “poetical”.

Bard of Erin: the Life of Thomas Moore by Ronan Kelly
Penguin Ireland, £25; 640pp Buy the book here

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