Reportedly his father did not wish him to enter the family's manufacturing business and instead he became the successful occupier of a large farm at Hampole near Doncaster. However, the death of his cousin William Leigh Brook in 1855 necessitated his return to Meltham, eventually coming the senior partner in the family firm. The 1861 Census records him residing at Bent House.
He joined the Meltham Local Board when it was formed in 1860 and remained a member for 25 years.
Meltham Local Board had launched legal objections to the Huddersfield Water Act of 1869 and were forced to pass on the associated legal costs to local rate payers. Concerned that the poorest in Meltham would be hit hardest by the rate increase, Brook paid around £400 so that they would not have to pay anything extra.
In 1874, he commissioned Sheffield artist Robert Mackley Gowland to paint a number of canvasses of horses. Over the course of around 3 weeks, Gowland spent time at Meltham Hall and occasionally stayed overnight at the Rose and Crown Inn. On the evening of 24 August, he appeared to be in good spirits but complained of a headache and retired to bed at the inn at around 10pm. It was not until around noon the following day before it was realised Gowland had not been seen again and John William Shaw, a worker at the inn, forced the bedroom door open — Gowland had committed suicide overnight and was found lying in a pool of blood. At the inquest, his wife Mary Ann stated that her husband had taken to alcohol and it seems he likely suffered from mental health problems. The jury returned a verdict that "the deceased had cut his throat in a state of temporary insanity."
Edward Brook purchased the Hoddom Castle estate in Dumfries, Scotland, from General Sharpe in 1877 for a reported sum of £200,500. In 1896 he purchased the Kinmount estate for £130,000.
In 1879, he paid for a carillon to be installed in the tower of St. Bartholomew. Built by Messrs. Gillett, Bland & Co., it consisted of 10 bells and could play 14 tunes, including "Abide with Me", "Rule Britannia", "Home, Sweet Home", "Auld Lang Syne" and "God Save the Queen". According to newspaper reports, a new tune was played each day over a fortnight.
In 1881, he began what became a local tradition of distributing new pennies to children on Collop Monday. In turn, this was carried on firstly by his son Charles Brook and then by his grandson, Edward William Brook, until at least the late 1930s.
In the mid-1880s and early 1890s, he partly waived the rents due by the tenants on Hoddom estate "in consequence of the continued depression in the value of agricultural produce and live stock" for several years in a row.
To celebrate Queen Victoria's Jubilee in 1887, he donated around 13 acres of land for the Jubilee Recreation Ground, which was formally opened in September 1888.
In the 1890s, he entirely funded the building of the Town Hall in Meltham, which was opened by his son Charles in February 1898. The offer of funding also included a gift of £1,500 "for the building of the offices, on condition that any balance not expended be returned to him" — upon his offer being read out to them, the members of the Meltham District Council reportedly broke out into singing "For he's a jolly good fellow"!
His other acts of munificence included donating a field for the construction of a gas works and 5½ acres of land near Harden Moss for a water supply reservoir, and the gifting of land for a proposed new cemetery. Whenever his workforce was placed on short time, "he made up the resulting deficiency in their wages." In their obituary article, the Yorkshire Post estimated that Brook had spent in excess of £15,000 to "advance the general welfare" of the people of Meltham.
In the summer of 1899, he was reported to have returned 6 month's worth of rent to the tenants on his estate.
In the early 1900s, it was reported that consideration was being given to erecting a bronze statue of Edward Brook outside the Meltham Town Hall.
In 1903 he purchased Wyborne Gate Villa at Southport (now Sunnymede School) and journeyed there in early January the following year to oversee the furnishing of the property. Whilst there, he caught a cold which quickly developed into something more serious and he returned home.
Edward Brook died on 29 January 1904 at Hoddom Castle, leaving an estate valued at £2,181,318 3s. 11d. In his Will, he bequeathed £5 to all of the full-time workers employed in the Brook's mills at Meltham Mills and at Spring Lane Mills, Holmfirth.
After a brief funeral service at Hoddom, his body was returned by train to Yorkshire, where he was buried on 3 February 1904 at St. James, Meltham Mills.
The Hoddom Castle Estate passed to his eldest son, Edward Jonas Brook.
Following her husband's death, Emma Brook moved to Beech Knoll in Oxted, Surrey, with her daughter, Mary Frances, where she died on 25 November 1912. She was buried at St. Mary, Oxted, on 28 November.