After attending Wesley College, Pearson worked as a stonemason for his father from 1885 to 1887 before emigrating to Canada in 1888.

[1] Pearson worked for Henry Sproatt beginning in 1890, and joined Darling, Curry, Sproatt, & Pearson in 1892, with fellow partners Frank Darling and S. George Curry.

In 1896 Sproatt left the partnership, and the firm was renamed Darling and Pearson.

Pearson's most significant project apart from this partnership is undoubtedly the Centre Block on Parliament Hill in Ottawa, a complex that contains the House of Commons of Canada and Senate of Canada, and the adjoining Peace Tower.

By 1920 the Centre Block was rebuilt with a design by Pearson and collaborator Jean Omer Marchand of Montreal.