He was born on November 2, 1828 at Jefferson, New Hampshire, United States. He was the seventh of the nine children of Deacon William and Nancy (Merrill) Plaisted. He was a descendant of Roger Playstead who settled in Kittery (now Berwick), Maine, about 1650.
Until the age of seventeen, Harris Merrill Plaisted made his home upon the farm where he was born.
He attended the district school at Jefferson, New Hampshire. His education was obtained largely during the fall and spring terms, first at Lancaster, New Hampshire, and later at academies in St. Johnsbury, Vermont, and New Hampton, New Hampshire. Summers he worked on the farm; winters he taught school.
He entered Waterville (now Colby) College in September 1849 and was graduated in 1853, meanwhile paying his way by serving as superintendent of schools in Waterville (1850 - 53) and principal (1853) of the Waterville Liberal Institute. He was graduated with highest honors from the Albany (New York) Law School in 1855, and studied one year in the office of A. W. Paine at Bangor, Maine.
Admitted to the bar in 1856, he practised in Bangor until 1861. He voted for Lincoln, taking an active part in the campaign and writing assiduously in behalf of the Union.
When the war began, he was appointed lieutenant-colonel by Governor Washburn, and raised a company in thirty days. On October 30, 1861, he became lieutenant-colonel of the 11th Maine Regiment and was promoted to a colonelcy May 12, 1862, in the midst of the Peninsular campaign. Transferred to the Southern Department, he commanded a brigade in the vicinity of Charleston, and during the siege of that city had charge of the famous gun, the "Swamp Angel. "
In April 1864, he was transferred with his so-called "Iron Brigade" to the Richmond sector. His three leaves, July 1862, February and November 1864, he spent in recruiting men for his depleted ranks, turning over the recruiting fees to the men themselves. Suffering with fever and ague, he was mustered out March 25, 1865, and after a month in a hospital returned to Bangor in the latter part of May 1865. For gallant and meritorious service he had been brevetted brigadier-general of volunteers, February 21, 1865, and major-general, March 13.
Resuming his law practice and entering politics, he twice represented Bangor in the legislature (1867, 1868) and was a delegate-at-large to the Republican National Convention of 1868, at Chicago. In competition with several able lawyers, among them Thomas B. Reed, Plaisted was elected attorney-general of Maine in January 1873. During his three years in this office, he secured twelve convictions in fourteen indictments for capital crimes. He resigned December 1, 1875.
He took the congressional seat left vacant by the death of Representative-elect Samuel F. Hersey. As one of the two Republican members of the select committee on trials for whiskey frauds under the chairmanship of J. Proctor Knott, he assumed the defense of Grant. He was firmly convinced of Grant's honesty and integrity, and, carefully presenting the results of his investigations, in the opinion of many completely vindicated Grant of complicity.
Declining reelection, he returned to Bangor in March 1877. In 1879 he left the Republican party on the money issue, maintaining that "greenbacks" should be substituted for bank bills which, when outstanding in the hands of the people, he held constituted a loan from the people to the banks without interest. In 1880 he was elected governor as the candidate of both Democrats and Greenbackers, but failed of reelection in 1883. His term in office was marked by a continuous conflict with the Republican council over political appointments. He was the Democratic nominee for senator in 1883, but was defeated.
From 1883 to his death he published and edited at Augusta The New Age, which under his influence was an able exponent of Bryan and bimetalism and a strong opponent of Blaine. He was the author of several trial reports; with F. H. Appleton, of The Maine Digest (1880), a digest of decisions of the state supreme court from 1820 to 1879; and also of several unpublished genealogical and autobiographical works.
His death, in Bangor, was due to Bright's disease resulting from malarial poisoning contracted in the army.
Harris Merrill Plaisted sucessfully commanded the 11th Maine Volunteer Infantry Regiment during the American Civil War and was promoted to the rank of Major General. During Plaisted's tenure in the US House, his time and effort was concentrated on his service as a member of the committee that investigated the Whiskey Ring, a major scandal that came to light during the Grant administration. Besides, he published The Maine Digest (a collection of Maine Supreme Judicial Court decisions), The Lowell Trial and The Wagner Trial.
He was a Republican before 1878, after 1878 he was Greenback.
He married first, September 21, 1858, Sarah J. Mason, who died in 1875, and second, September 27, 1881, Mabel True Hill. Three sons were born to the first marriage and one daughter to the second.
