Normanby was the son of Henry Phipps, 1st Earl of Mulgrave and Martha Sophia, daughter of Christopher Thompson Maling.

However, in the summer of 1819, he began to break with his family's Tory politics, and signalised his conversion to the Whigs by joining Brooks' Club on 3 December.

His brother Charles kept up the family interest with the Scarborough corporation, and Normanby was returned in absentia in March, despite being politically at odds with his father.

An attempt was made to have him put in at St Ives at a by-election in 1821, but support proved to be lacking, and Normanby withdrew without contesting the seat.

The illness and death of William Plumer in the beginning of 1822 allowed him to take his seat in February for Higham Ferrers, a pocket borough of the Whig grandee Earl Fitzwilliam.

[1] He declined to be nominated again for Malton in 1830, anticipating the imminent death of his father, and was thus out of Parliament when Lord Grey formed a government in November 1830.