 After he became High Sheriff in 1885, he served a breakfast for 10,000 people of the local population.Williamson's philanthropy in Lancaster over the years, through many gifts, subscriptions, and buildings, amounted to more than £500,000 ().In the 1886 general election, Williamson was elected to the House of Commons as Member of Parliament (MP) for Lancaster, and held his seat at the 1892 election.