Following an education at the Royal Belfast Academical Institution, in 1862, he entered the firm of Harland and Wolff. So meteoric was his rise that by 1874 he had been made a partner. He would remain with the firm all his life. Pirrie nurtured a close and lucrartive working relationship with first Thomas Henry Ismay and later his son, Joseph Bruce Ismay who led the White Star Line. Harland and Wolff was the sole constructor for White Star, building its ships to the highest specifications on what was termed a "cost-plus" basis.