The brothers, Owen & Thomas McCarthy, were born in Ireland to Michael McCarthy and wife.  They migrated to the United States
Thier father died in Denison at the age of 65 years in at the turn of the century, June 1900, and was buried in Calvary Cemetery, Denison, along with his family.

Denison Daily News
January 8, 1880
Pg. 3 

McCARTHY & CO.
The Mammoth Hardware House of North Texas
This house was established in 1873 and covers an area of 7,500 square feet.  It is with pride to our city that we call the attention of our patrons to this firm who commenced business here seven years ago, on the corner of Main street and Rusk avenue, and one of the most successful business houses in Denison, and to-day has as large a trade as any house in North Texas.  Their business extends over a radius of 100 miles, and Owen McCarthy says their customers will come 50 miles out of their way to trade with them.  They possess an enviable reputation for fair, legitimate and honest dealing – every bearing in mind that low prices and good goods are what draw.  Like the frugal, industrious miner when he finds a bonanza – he shouts at the top of his voice, “Eureka!” “I found it!”  The same has been that McCarthy does to-day a thriving business.
We can safely say that they have made, legitimately, fifty thousand dollars since they have established business here.  Owen McCarthy, who is the business and financial manager, is a shrewd and far-sighted old man, and twenty years experience in the hardware trade has taught him that goods well bought are half sold.  He could see the boom coming in the past, in the tremendous advance in iron and hardware and laid in double the stock that he usually purchases for fall trade.  As a result the firm has made at least ten thousand dollars by the advance, and can sell 25 per cent lower than other houses and then realize a handsome profit.  No wonder then McCarthy & Co. have a large trade.  Success and wealth flows in upon them, for they are respected as one of the lucky pioneer houses of Denison. 

The Sunday Gazetteer
Sunday, September 27, 1885
pg. 3
TRUTH IS MIGHTIER THAN FICTION
The Leading Hardware, Stove and Furniture House of Denison
For fair, honest and legitimate dealing no house possesses more honor and has been crowned with more success.  Four years ago the old pioneer hardware house purchased an extensive stock of furniture, consisting of fine parlor and chamber suits, ranging in prices from $25 to $30, and bedsteads as low as $1.25.
...you can buy of Owen McCarthy anything and everything to go to house keeping with, from a needle to a chair...Look at those figures and see if the expense of marrying is as expensive as you imagine....you will have to purchase only the following articles to complete your outfit for house keeping: One cook stove, one bedstead, one bureau, one wash stand, one table, six chairs, one rocker, one parlor set, one mattress, one spring mattress, one lamp, one set each of cups and saucers, and plates, tea and table spoons, knives and forks

The Sunday Gazetteer
Sunday, October 5, 1890
pg. 4

Owen McCarthy of this city was many years ago a prominent merchant of Albion, N.Y., where he broke up in business and left, owing his creditors about $15,000.  He came to Denison in the early days when it was known throughout the country as the "Infant Wonder" and made a fortune here, which he is now enjoying.  Recently he returned to Albion for the first time since he left there, and to the astonishment and delight of his creditors, who had lost all trace of him, paid them in full with accumulated interest what he owed them.  It was an act of rare honesty.

The son of Denison hardware merchant, Owen McCarthy, Jr., was 14 years old on Christmas Eve 1892.  His attorney argued that any law prohibiting a person from carrying a pistol is customarily suspended at Christmas, especially if the person in question is a child who means no harm.