From 1858 to 1900 he was a partner in B.E. Cook & Son (he was the son). Both he and his father, Benjamin, were silversmiths, jewelers and watchmakers.

Enlisted as a sergeant in Company C 52nd Infantry Regiment, Mass Vols on 9 September 1862 at Camp Miller, Greenfield. Promoted to Full Sergeant on 2 October 1862. Mustered out on 14 Aug 1863 at Camp Miller, Greenfield, MA.

He served as the first mayor of Northampton on its incorporation as a city in 1884. He won re-election in 1885 and 1886.

B E Cook, 89, Dies; Was First Mayor of Northampton
Served Three Terms, being Unopposed Last Time-Known as a Speaker
Was a 'Grand Old Man' in Municipal Affairs
Served as Selectman Under Town Government, Held Many Other Offices – Served in Civil War
Northampton, Dec 14 – Benjamin E Cook, 82, first mayor of Northampton, died this morning at 8.30 at the Dickinson hospital, where he was taken after an illness of two months, during which he received devoted attention at his home, 83 Pomeroy terrace…
Friend of Judge J B O'Donnell
Mr Cook was, perhaps, Northampton's leading political orator. On his own side of the political fence was the late Judge John B O'Donnell, Mr Cook's closest political friend, and one of his closes personal friends, who was a leading promoter of Mr Cook's first nomination for mayor in 1883…Besides their association in politics, the two were associated in real estate...
The two factors that most contributed to Mr Cook's platform success were his extraordinary retentive memory and his storm manner of speech. He could fairly be called an orator, but not a silver-tongued orator. His speech was explosive and commanding. It was not his method to open with a calm manner and smooth phrases, but to start a bombardment at once, which provoked early applause and was sustained to the end.
Had Remarkable Memory
His amazing memory of both local and national events made him an unfailing source of information to his coworkers and enabled him to marshal his arguments in a political address with an effect that was highly stimulating to his own side and correspondingly crushing to the opposition. He was fully recognized as a dangerous antagonist in a political debate.
The personality of Mr Cook was reflected in his manner of public speaking. He was forthright in his contacts with others and dealt in snoteity and equivocation not at all. His sobriquet of "Honest Ben Cook", given to him in relation to his public service, applied to all his dealing. Throughout his long career, he was recognized and trusted as the friend of all the people. Mr Cook was a staunch friend and a generous opponent. His loss in a community loss and wider and the esteem and affection in which he was held was bounded by no barriers of politics, creed or race.
Mr. Cook was a brother of the late Admiral Francis A Cook…
Served in Civil War
Benjamin E Cook was born February 14, 1841, on the Cook homestead on Bridge street, the son of Benjamin E and Elizabeth Griffin) Cook. He attended the graded and high schools and the Lewis J Dudley private school on Gothic street. At the age of 16, he entered the jewelry store of his father and at the age of 20 enlisted in the 52d Massachusetts regiment for service in the Civil war. He was made 2d sergeant of Co C of Northampton. Before going to war, he had been a member of the local militia company and of the volunteer fire department. He was a member of the famous old Deluge company, and, subsequently, was foreman of the hook and ladder company.
The year Mr Cook returned from war, 1864, he was taken into partnership with his father. The partnership continued until the death of Gen Cook in 1900 at the age of 96. The same year Mr Cook sold the jewelry business to Phelps & Gare. Before and after his retirement from the jewelry business, Mr Cook engaged in the development of real estate. He built the block at Pleasant and Armory streets now occupied by Quinn's furniture business. Eastern Avenue was developed by Mr Cook, and Woodbine avenue by Mr Cook and John B O'Donnell, two ex-mayors, who had long been associated in friendship, business and politics.
Was City's First Mayor
The political career of Mr Cook began with his service as selectman of the town of Northampton in 1876...When the town was made a city in 1884, Mr Cook was elected first mayor, and continued in that office three years. In election for his third term, no opponent was nominated against him, a distinction that has fallen to the lot of only one other mayor, Alvertus J Morse. Mr Cook served on the board of water commissioners and the board of sewer commissioners, and gave two widely separated periods of service on the school board.
Mr Cook was a member of the Democratic city committee at least 50 years, and probably longer, though the years were not all consecutive, and had been chairman of the Democratic county committee...Mr Cook had been a director of the First National bank and a trustee of the Northampton Institute for Savings nearly 50 years. He was associated with Judge Richard W Irwin in settlement of the affairs of the Hampshire County National bank and the Hampshire Savings bank in 1898. He was a director of the Connecticut Valley Street Railway company, which built lines to Amherst and Greenfield. He and his brother, Rear Admiral Francis A Cook, established the illuminated clock in the tower of the First church as a gift to the city in memory of Gen Benjamin E Cook, their father. Mr Cook was a member of W L Baker Grand Army post and president of the 52d Regimental association.
Two Notable Parties
Mr Cook entertained two notable parties in connection with his political career. In 1911, he entertained the Democratic city committee at the Hampton hotel in observance of his 70th birthday, and was presented a loving cup, and in 1917 he entertained the ex-mayors' club at the Draper hotel in observance of his 76th birthday. The ex-mayors present on the latter occasion, besides Mr Cook were: A G Hill, Judge J B O'Donnell, Judge H P Field, John L Mather, Arthur Watson, James W O'Brien and William H Feiker. The living ex-mayors who were unable to attend the affair were H C Hallett, T M O'Connor and Lieut-Gov Calvin Coolidge.
Mr Cook's first wife was Anna Elizabeth Smith, daughter of George E and Hetty R (Jones) Smith of Northampton. Mrs Anna (Smith) Cook died a number of years ago, and Mr Cook married, April 9 1924, Annie E, widow of John M Newton, a prominent business man of Boston. Mrs Cook is the daughter of the late M V Pierson and sister of the late Elmer R Pierson, prominent business men of Norwich, Ct. Mr Cook leaves two daughters, Dr Elizabeth Christine Cook, a professor at Columbia university, and Mrs Floyd Newton, a member of a New York High school faculty; two stepdaughters, M A C (Newton) Stender and Mrs Clark (Newton) Kaup, both of Pittsburg, Pa., and two stepsons, Floyd Newton of New York and Russell E Newton of Northampton. Miss Helen Cook of Bridge street, who died in June, was the last member of Gen B E Cook's family of six children, except ex-Mayor Cook.
The funeral will be held Tuesday afternoon at 2.30 at the Edwards church. Rev C Russell Prewitt, pastor of the Methodist church, will officiate assisted by Rev J N Armstrong of the Edwards church and burial will be in Bridge street cemetery.
(Springfield Daily Republican, Monday 15 December 1930, pp 1,5)