Emily first met Alfred, Lord Tennyson when she was nine or sixteen.
Alfred fell in love with Emily at the marriage of his brother Charles to her sister Louisa in May 1836. He later wrote a sonnet about how he felt at the wedding of their siblings, where Emily was the bridesmaid.
In 1837, they were engaged. It was called off in 1840, because of financial issues and her father's wariness of Tennyson's ability to support a family on a poet's income. Tennyson's career was more successful in the 1840s and they were married on 13 June 1850.
She was his secretary, business partner, proofreader, and financial manager.
They had two sons, Hallam, born at Twickenham on 11 August 1852, and Lionel, born at Farringford House on 16 March 1854. After the birth of her second son, she developed an incurable illness.
A musician, Emily employed her own talents in setting some of his poems to music. She wrote the hymns Great God, who knowest each man's need and O yet we trust that somehow good. Emily and her son Hallam wrote a memoir of Tennyson.
Over time, the degree of responsibility was so stressful that it weakened her health. She longed for periods "for reading and thinking, to restore the elasticity of one's mind, now too like a bow spoilt by long bending". She became an invalid and was no longer able to entertain or perform managerial and secretarial duties, as she had in the past. This was in some ways a blessing to Alfred, with both of them going into retirement. She was able, though, to offer him comfort when he was upset.
Alfred died in 1892. He was buried at Westminster Abbey in Poets' Corner. Emily Tennyson died on 10 August 1896 at Aldworth. She is buried in All Saints' Church, Freshwater, Isle of Wight.