Career
Leeman was deputy chairman of the successor company, North Eastern Railways, from 1855 to 1874 and chairman from 1874 to 1880, having encouraged its formation through mergers in 1854, and he was a chairman of the Railway Association of Great Britain. Leeman resigned as chairman of the NER in 1880 after the failure of his mining company reduced his wealth and harmed his health. Other business
He was involved the 1860s in developing iron ore mining at Rosedale for Teesside steel works, co-owning the Rosedale and Ferryhill Iron Company from 1860 to 1877.
He was a director of the York Herald and chairman of the Yorkshire Banking Company from 1867 to 1880.
He became a Liberal councillor for Castlegate Ward in 1836 and for Guildhall Ward in 1839, and was an Alderman for 28 years from 1850. When Anthony Trollope campaigned in Beverley as a Liberal candidate, Leeman warned him against lieutenant
Trollope came last due to corruption and vote-buying.