Mitchell, who described himself as ‘a zealous and consistent Liberal’, was born at Aberdeen, the first son of Alexander Mitchell, the cashier of the Aberdeen town and county bank.
In June 1863 Mitchell offered as a Liberal for a vacancy at Berwick-upon-Tweed created by the death of the sitting member, but after a fractious contest, he was defeated by his Conservative opponent. Although he petitioned against the return on the grounds of bribery and corruption, 13 July 1863, the election committee upheld the result, 4 Mar. 1864. Contesting the seat again in 1865, he called for a substantial extension of the franchise while insisting that he would not support the disenfranchisement of freemen, and after a highly partisan campaign, in which he described the Conservative party as being ‘actuated by the desire to oppose all progress’, he was returned in second place.
Although his attendance was often curtailed by poor health, Mitchell divided loyally with the Liberals on most major issues. He backed the Russell ministry’s reform bill, 27 Apr. 1866, and the defeated redistribution bill, 18 June 1866, which precipitated the government’s resignation. With the Liberals in opposition, he divided with Gladstone on all the main features of the representation of the people bill, and, as a staunch opponent of the Maynooth grant and the regium donum, he voted for his leader’s resolutions on the Irish church, 3 Apr. 1868.
Mitchell rarely spoke in debate, and his two known interventions on electoral reform met with little success. During the debates on the representation of the people bill, he proposed the division of every two-member borough into two districts with a separate register, with each district returning one member to Parliament independent of the other, arguing that such a scheme would diminish bribery and give minorities more effective representation, 17 June 1867. The proposal garnered some cautious support in the House, but, citing his wish not to impede the passing of the bill, he withdrew the amendment.
His health failing, Mitchell retired from public life at the dissolution in 1868. He died at his home in Great Stanhope Street, London, in May 1873.
