He was educated at Upper Canada College before leaving in 1876 to join his father's stock brokerage company, Pellatt and Osler, as a clerk.

Much of Pellatt's fortune was made through investments in the railway and hydro-electric industries in Canada, including the Toronto Electric Light Company.

However, legislator Adam Beck launched a campaign against the great industrialists of Canada, proclaiming that hydro power "should be as free as air".

[6] Through legislative process and by whipping up anti-rich sentiment, Beck was able to successfully appropriate Pellatt's life work and take his electric companies from him.

[citation needed] Beck then led a populist revolt to raise Pellatt's taxes on his castle, Casa Loma, from $600 per year to $12,000.

[citation needed] The strain of losing all of his income, coupled with the large increase in property taxes for his castle, led him to rely solely on his real estate investments, which were unsuccessful due to the beginning of the First World War.

After the province expropriated his electrical power generating business[citation needed], and his aircraft manufacturing business was appropriated by Beck as part of the war effort during the First World War, Pellatt was driven to near-bankruptcy, which forced him and Lady Pellatt to leave Casa Loma in 1923.

Prior to building Casa Loma, Pellatt sold his summer retreat in Blantyre / Fallingbrook area of southwest Scarborough to his son Reginald and other parts of the estate to others; Chateau des Quatre Vents at 3025 Queen Street East was built in 1892 by William T. Murray on land acquired from Pellatt former summer estate.

[10] After he died on March 8, 1939, thousands of people lined Toronto streets to witness his funeral procession, and he was buried with full military honours.

[12] The film, narrated by Colin Mochrie, is shown continuously in the theatre at Casa Loma, which is located where the swimming pool was planned to be.