[1] Through his maternal aunt, Mercy (née Burgess) Dawes, he was a first cousin of Republican Senator and Representative Henry L.

[1] In 1835, when he was only 24, Whitney was elected and commissioned brigadier general of the 2nd Brigade of the Massachusetts State Militia, which he was largely influential in reorganizing.

In 1854, Whitney was appointed superintendent of the federal armory at Springfield, Massachusetts, by President Franklin Pierce, holding the position until 1860.

When Whitney left the Springfield Armory in 1860, President Buchanan appointed him Collector of Customs for the Port of Boston.

In February 1866, he joined Boston interests in organizing the Metropolitan Steamship Company, of which he was elected president.