Dalton's father was a ship's captain turned merchant, involved in trade with Europe and the West Indies, and was instrumental in securing the separation of Newburyport from Newbury.

He was elected to the Massachusetts Provincial Congress and the Newburyport board of selectmen in 1774, and was an active proponent of independence after the war broke out.

In the 1791 election (US Senators were then chosen by vote of the state legislature), Dalton ran a distant fourth against George Cabot, the eventual victor, and others.

He filled the seat vacated by William Cranch who was appointed to the bench in the new capitol and served for a little over a year until the Board of Commissioners of the Federal City was disbanded in 1802.

When the site of the nation's capital was selected, Dalton sold off most of his property in Massachusetts, and speculatively purchased land in Washington, D.C.

In order to make ends meet, Dalton was given a patronage appointment as surveyor of the port of Boston, serving from November 1814 until his death on May 30, 1817.