He attended Cazenovia Seminary. In New York, he studied law and taught primary school.
In 1878, McDonald moved to Fort Scott, Kansas where he served as an apprentice at the law offices of Joseph South. Lorrence. He was admitted to the bar in 1880. McDonald then moved to the White Oaks, New Mexico Territory in 1880 and settled in Lincoln County.
Staking out mining claims and working as a mineral surveyor, he managed and later purchased the Carrizozo Cattle Ranch Company.
He became a United States deputy mineral surveyor for New Mexico in 1881. He became active in Democratic politics.
McDonald was Lincoln County Assessor from 1885 to 1887. The couple had five children.
He chaired the Lincoln County Board of Commissioners from 1895 to 1897.
Securing the Democratic nomination, McDonald was elected the first Governor of the state of New Mexico on November 7, 1911. During his tenure, the state"s government was structured while raids by Mexican bandits were dealt with. After his governorship, McDonald was appointed and served as New Mexico Fuel Administrator, an office he held until his death.
McDonald died on April 11, 1918 and is interred at Cedarvale Cemetery in White Oaks.
In 1891, he was a member of the New Mexico Territorial House of Representatives. A member of the New Mexico Cattle Sanitary Board from 1905 to 1911, he also chaired the 1910 Democratic Territorial Central Committee.