A professor of classics at Queen's in the 19th century, Mackerras was known to contemporaries as "The Martyr of Queen's" for his self-sacrifice while fundraising for the university.
Mackerras was born in Scotland and raised in Lyn, Ontario. He was educated at Queen's (BA 1850, MA 1852) and appointed Professor of Classics at the university in 1864.
Several years later, in 1867 and 1868, Queen's suffered two potentially disastrous financial blows when the province withdrew its funding from Queen's and the Commercial Bank collapsed, taking two-thirds of the university's endowment with it.
In 1868 and 1869, Principal William Snodgrass, Mackerras, and a few other determined officials spent almost a year canvassing through the cities, towns, and backwoods farms of Ontario and Quebec.
The work saved Queen's but it permanently destroyed Mackerras' health. He taught at Queen's in constant sickness for another 10 years, barely able to climb the stairs to his classes.
He died from his illness in 1880 and is buried in the Cataraqui Cemetery.