Elizabeth Cobbold, née Knipe, was born in London, England. Her father Robert Knipe was a merchant and a director of the London Assurance Corporation. At age 19, she published her first collection of poetry, Poems on Various Subjects (1783), under the name Eliza Knipe. At 26, she married her first husband, William Clarke, some 35 years her senior, a comptroller of customs, who died a few months after their wedding. She remarried shortly afterwards in 1791 to John Cobbold, a wealthy brewer in his 40s with 17 children. That same year, she published her first novel, The Sword, or Father Bertrand’s History of his own Times; from the Original Manuscript (1791) under the name Elizabeth Clarke.
She and John Cobbold had 7 more children together over the next 10 years, and she juggled domestic duties with writing and active involvement in Ipswich social, philanthropic, artistic, and scientific circles. She also used the pseudonym Carolina Petty Pasty. In 1803, she served as editor of a volume of poems by Ann Candler. She became known for creating St. Valentine's Day cards with her verses attached to cleverly cut paper, and published many of them in 1813 and 1814 as Cliff Valentines. After Elizabeth's death, Laetitia Jermyn edited and published a collection of her poetry called Poems, with a Memoir of the Author (1825). Charles Dickens is said to have used her as the model for his character Mrs. Leo Hunter in The Pickwick Papers.