He was made a KCB for his civil services on 25 March 1859. In 1861 and 1862 he served on commissions appointed to consider the construction of embankments of the River Thames, and of communications between the embankment at Blackfriars Bridge and the Mansion House, and between Westminster Bridge and Millbank. He died suddenly on 26 June 1863 and was buried in Brookwood Cemetery. His successor as Survey General of Prisons was another Royal Engineers officer, Major Edmund Henderson. Jebb married twice; first, on 14 June 1830, to Mary Legh Thomas, daughter of William Burtinshaw Thomas, of Highfield, Derbyshire, who died in 1850, and by whom he had a son, Joshua Gladwyn, and three daughters. He was remarried on 5 September 1854, to Lady Amelia Rose Pelham, daughter of Thomas Pelham, the Earl of Chichester, who survived him.