Bagallay sat as a Conservative Party Member of Parliament (MP) for Hereford from 1865 to 1868. He was knighted on 14 December 1868 after losing his seat, but was re-elected in 1870 as MP for Mid Surrey, holding the seat until 1875. He served briefly as Solicitor-General under Benjamin Disraeli in 1868 and again in 1874, and as Attorney-General under Disraeli from 1874 to 1875. In 1875, he was sworn of the Privy Council and appointed to the newly established Court of Appeal, where he served until his death in 1888.
Judgments
Parker v South Eastern Railway [1877] 2 CPD 416 - English contract law on exclusion clauses holding that an individual cannot escape a contractual term by failing to read the contract, but that a party wanting to rely on an exclusion clause must take reasonable steps to bring it to the attention of the customer.
The Household Fire and Carriage Accident Insurance Company (Limited) v Grant (1878–79) LR 4 Ex D 216 - Contract law] concerning the "postal rule", and containing an important dissenting judgment by Bramwell LJ, who wished to dispose of it.
Re Hallett's Estate (1880) 13 Ch D 696 - English trusts law concerning asset tracing, Baggallay LJ concurring with Fry LJ.
Redgrave v Hurd (1881) 20 Ch D 1 - Contract law concerning misrepresentation and holding that a contract can be rescinded for innocent misrepresentation, even where the represent had the chance to verify the false statement; Baggallay concurring with Jessel MR.
Hutton v West Cork Rly Co (1883) 23 Ch D 654 - UK company law case concerning the limits of a director's discretion to spend company funds for the benefit of non-shareholders; Baggallay dissenting the decision of Cotton LJ and Bowen LJ.
Smith v Land and House Property Corp (1884) LR 28 Ch D 7 - Contract law case, concerning misrepresentation and holding that a statement of opinion can represent that one knows certain facts, and can amount to misrepresentation; Baggallay LJ concurring with Bowen LJ
Personal life
He married, on 25 February 1847, Marianne, youngest daughter of Henry Charles Lacy of Withdean Hall, Sussex, by whom he left issue.
In later years Baggallay suffered from poor health and died while convalescing in Hove, Sussex. He was buried at South Metropolitan Cemetery at Norwood.