Mack holds records for the most wins (3,731), losses (3,948), ties (76), and games managed (7,755) in Major League Baseball (MLB) history.

However, constant financial struggles forced repeated rebuilding of the roster, and Mack's teams also finished in last place 17 times, including ten seasons in which the Athletics lost 100 games.

Connie Mack never legally changed his name; on the occasion of his second marriage at age 48, he signed the wedding register as "Cornelius McGillicuddy".

[9] Mack was educated in East Brookfield, and began working summers in local cotton mills at age 9 to help support his family.

[10] He quit school after completing the eighth grade at age 14, intending to work full-time to contribute to the family's support, as several of his siblings had done.

In December 1890 Mack signed a contract with the Pittsburgh Pirates of the National League and remained with them for the rest of his career as a full-time player.

"[This quote needs a citation] In addition to verbally needling batters to distract them, he developed skills such as blocking the plate to prevent base runners from scoring and faking the sound of a foul tip.

Fired on September 21, 1896,[22] he retired as a full-time player and accepted a deal from Henry Killilea to act as manager and occasional backup catcher for the minor league Milwaukee Brewers (the modern-day Baltimore Orioles).

[28] According to James, Mack looked for seven things in his players—"physical ability, intelligence, courage, disposition, will power, general alertness and personal habits.

"[26] He was "one of the first managers to work on repositioning his fielders" during the game, often directing the outfielders to move left or right, play shallow or deep, by waving his rolled-up scorecard from the bench.

[33] James summed up Mack's managerial approach as follows: he favored a set lineup, did not generally platoon hitters; preferred young players to veterans and power hitters to those with high batting averages; did not often pinch-hit, use his bench players or sacrifice much (even so, the A's led the league in sacrifice bunts in 1909, 1911 and 1914); believed in "big-inning" offense rather than small ball; and very rarely issued an intentional walk.

His original team, with players such as Rube Waddell, Ossee Schrecongost, and Eddie Plank, won the pennant in 1902 (when there was no World Series) and 1905.

The 1927 Athletics featured several future Hall of Fame players including veterans Ty Cobb, Zack Wheat and Eddie Collins as well as young stars like Mickey Cochrane, Lefty Grove, Al Simmons and rookie Jimmie Foxx.

[37] According to Bill James, by the time Mack recovered again financially, he was "old and out of touch with the game, so his career ends with eighteen years of miserable baseball.

His business style was no longer viable in post-World War II America due to various factors, including the increased expense of running a team.

On that date, his sons Earle, Roy and Connie, Jr. persuaded their father to promote Jimmy Dykes, who had been a coach since 1949, to assistant manager for the remainder of the season.

This was one reason he was constantly collecting players, signing almost anyone to a ten-day contract to assess his talent; he was looking ahead to future seasons when his veterans would either retire or hold out for bigger salaries than Mack could give them.

Even as bad as the A's got during the next two decades, he stubbornly retained full control over baseball matters long after most teams had hired a general manager.

Yearly payments of $200,000 drained the team of badly needed capital, and ended any realistic chance of the A's winning again under the Macks' stewardship.

The other American League owners had been concerned for some time about the situation in Philadelphia, since the crowds at Shibe Park had dwindled to the point that visiting teams could not meet their expenses for traveling there.

Prior in 1951, Buffalo based businessman and Sportservice owner Louis Jacobs gave Mack a loan of $250,000.00 with no interest to keep the Athletics from having financial difficulty.

A final attempt to sell the A's to Philadelphia car dealer John Crisconi briefly gained Mack's support, but collapsed at the eleventh hour—reportedly due to behind-the-scenes intrigue by the Yankees.

Johnson immediately requested permission to move to Kansas City, which was granted after Detroit's Spike Briggs switched his vote.

[36] Although Mack had long since conceded that his 55 years in the American League were over, his doctor reported that the nonagenarian owner suffered a sudden sharp drop in blood pressure and almost expired upon learning that his team was gone.

Officially, it was announced that he died of "old age and complications from his hip surgery"[50] Mack's funeral was held in his parish church, St. Bridget's, and he was buried in Holy Sepulchre Cemetery in Cheltenham Township[51] just outside Philadelphia, with Commissioner of Baseball Ford Frick, the AL and NL presidents, and all 16 MLB owners serving as pallbearers.

[40] His friend Red Smith called him "tough and warm and wonderful, kind and stubborn and courtly and unreasonable and generous and calculating and naive and gentle and proud and humorous and demanding and unpredictable".

Mack himself was upset by these allegations: when some writers accused him of deliberately losing the second game of the 1913 World Series in order to extend the series and make more money in ticket sales, he uncharacteristically wrote an angry letter to the Saturday Evening Post to deny it, saying "I consider playing for the gate receipts ... nothing short of dishonest."

Mack lived through the entire era of racially segregated baseball; the early days of the game in his youth sometimes featured black players, but this ended by the 1890s and the major leagues remained white-only until Jackie Robinson broke down the color barrier in 1947, and even afterwards Mack never displayed any serious interest in signing black players.

His second wife was Catherine (or Katharine) Holahan (or Hoolahan) (1879–1966); the census records have various spellings (the wedding register reads "Catarina Hallahan").

The couple had four daughters and a son, Cornelius Jr. A faithful Catholic his entire life, Mack was also a longtime member of the Knights of Columbus (Santa Maria Council 263 in Germantown, which moved to Flourtown, Pennsylvania in the 1980s).