Gertie Millar was born in Bradford, Yorkshire (UK), in 1878. She grew up to be tall, thin and attractive with dark hair and large limpid eyes. She was also tough, determined and ambitious. Her stage career began as a singer and dancer in the many music halls of Yorkshire. Later, she moved to London where she was soon topping variety bills, earning substantial sums and attracting much attention.

In 1901, George Edwardes (the famous theatre manager and originator of the British musical comedy, who, the previous year, had lost his star, Marie Tempest, after a disagreement over a costume) recruited Gertie Millar to be the leading lady in his productions at the Gaiety Theatre. Her first starring role was in The Toreador.

Her next show was Our Miss Gibbs that opened at the Gaiety on January 23, 1902. Its strong cast included George Grossmith jr., Robert Hale, Edmund Payne, Denise Orme, Jean Aylwin, Gladys Homfrey and Kitty Mason, but Gertie Millar was, without doubt, the star and made her the best known musical comedy performer in the country. The music was written, in collaboration with Ivan Caryll, by Lionel John Alexander Monckton (1861-1924), an Oxford University educated lawyer turned composer who married Gertie Millar. The hit song of the show was 'Moonstruck', a song Monkton had written especially for his wife.

He was to write the music for nearly all her following successes, including her next show -  A Country Girl (1902) that ran for an astonishing 729 performances. In July, 1903, the Gaiety closed for a total refurbishment. The closing show was The Linkman; or, Gaiety Memories. Gertie Millar starred as Morgiana, recreating the part original played by Kate Vaughan in the 1880 burlesque The Forty Thieves.

On October 26, 1903, in the presence of  His Majesty King Edward VI and Queen Alexandra, the new Gaiety opened with the premiere of the musical comedy The Orchid in which Gertie Millar. The show ran for 559 performances.

Success after success followed during the next decade. During the 1905/6 season, it was Spring Chicken with music again written by Monckton in collaboration with Ivan Caryll, plus a song written by Jerome David Kern (1885-1945).

On November 24, 1906, Gertie Millar The New Aladdin opened at the Gaiety. Gertie Millar was the star with an impressive cast that included George Grossmith Jnr.,  Robert Nainby, Harry Grattan, Alfred Lester, Edmund Payne and Adrienne Augarde. The show ran until April 27, 1907.

  The Girls of Gottenberg, again with Monkton's music (and one of the lyrics by P G Wodehouse) opened at the Gaiety Theatre on May 15, 1907 and ran till March 28, 1908. This was followed for the 1908/9 season by A Waltz Dream with the music of Oscar Straus (1870-1954). In 1910, Gertie Millar starred in one of the most best-loved Gaiety musical comedies, The Quaker Girl. Her co-star was Joseph Coyne (1867-1941) the American actor who has created a sensation with Lily Elsie in The Merry Widow (1907). His 'Dancing Lesson' with Gertie Millar repeated the enormous success of the 'Merry Eidow Waltz' he had performed in the previous show. The Quaker Girl ran for 536 performances.

Gertie Millar's next show, in the spring of 1912, was Franz Lehar's Gipsy Love. This was followed by The Dancing Mistress that opened at the Adelphi Theatre in London's Strand on October 19, 1912. Gertie Millar again was the star with a cast that included Joseph Coyne, James Blakeley, Gracie Leigh, Elsie Spain and  Maud Cressall. A great success, the show ran for 241 performances (although, towards the end of the run, Gertie Millar's part was taken by Phyllis Dare and Daisy Elliston).

There were two more long-running comedies in which Gertie Millar starred - The Marriage Market (1913) at Daly's Theatre and Bric-a-Brac (1915) at the Palace.

By the time the show ended, the world was much changed - war waged, people's tastes had irrevocably changed and they were now flocking to the comfort of the new cinema palaces for their escapism, Gertie Millar's husband was in poor health and had ceased composing and, in 1915, George Edwardes (for whom she had worked for over fourteen years) died. For a while, Gertie Millar performed occasionally in the variety theatres where her career had begun. In 1918, she made her final appearance at the Alhambra Theatre in Bradford, the city where she had been born.

In 1924, her husband died. Some time afterwards, Gertie Millar married William  Humble Ward, the second Earl of Dudley (1867-1932). Before the war, he had been the governor-general of Australia. On June 6, 1920, his first wife had been drowned in a swimming accident at their estate in Ireland.
Gertie Millar, the working-class girl from Yorkshire who grew up to be one of the best loved stars and most photographed women of the Edwardian era, had become Lady Dudley.