Mack's last three seasons in the National League were as a player-manager with the Pittsburgh Pirates from 1894 to 1896, with a 149–134 (.527) record.
Fired on September 21, 1896, 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.
He agreed to a salary of $3,000 (equivalent to $90,000 in 2019) and 25% of the club.
He managed the Brewers for four seasons from 1897 to 1900, their best year coming in 1900, when they finished second.
It was in Milwaukee that he first signed pitcher Rube Waddell, who would follow him to the big leagues.

In 1901 Mack became manager, treasurer and part owner of the new American League's Philadelphia Athletics.
He managed the Athletics through the 1950 season, compiling a record of 3,582–3,814 (.484) when he retired at 87.
Mack won nine pennants and appeared in eight World Series, winning five.

Mack's 50-year tenure as Athletics manager is the most ever for a coach or manager with the same team in North American professional sports, and has never been seriously threatened.
A few college coaches had longer tenures: John Gagliardi was a head football coach from 1949 to 2012, ending with 60 seasons at Saint John's of Minnesota; Eddie Robinson was head football coach at Grambling State for 57 seasons, from 1941 (when it was known as the Louisiana Negro Normal and Industrial Institute) to 1997; and the upcoming 2018–19 season will be the 52nd for Herb Magee as head men's basketball coach of the institution now known as Jefferson (1967–present).
Joe Paterno, with 62 seasons as a college football coach for the Penn State Nittany Lions also surpassed Mack, although Paterno was head coach in only 46 of those years.
College football pioneer Amos Alonzo Stagg also surpassed Mack in overall tenure, though not in tenure for a single employer; he was a head coach for 55 seasons in all (1892–1946), with the first 41 at Chicago (1892–1932).

Mack was widely praised in the newspapers for his intelligent and innovative managing, which earned him the nickname "the Tall Tactician".
He valued intelligence and "baseball smarts," always looking for educated players. (
He traded away Shoeless Joe Jackson despite his talent because of his bad attitude and unintelligent play.) "
Better than any other manager, Mack understood and promoted intelligence as an element of excellence."
He wanted men who were self-directed, self-disciplined and self-motivated; his ideal player was Eddie Collins.
According to baseball historian Bill James, Mack was well ahead of his time in having numerous college players on his teams.
Several of his players went on to become well-respected college coaches.
Jack Coombs, the ace of Mack's 1910-11 champions, became the longtime coach at Duke.
Andy Coakley, who won 20 games for Mack's 1905 pennant winners, coached for over 30 years at Columbia, where he was the college coach for Lou Gehrig.
Dick Siebert, longtime coach at Minnesota, played for Mack from 1938 to 1945.
James believed that Mack's influence on the game, as great as it was, would have been even greater had the college game been more popular during the 1920s and 1930s, when Mack was at his peak.

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

As a result of Mack's striving to have his players become better people as well as baseball players, he created a Code of Conduct following the 1916 season:
I will always play the game to the best of my ability.

I will always play to win, but if I lose, I will not look for an excuse to detract from my opponent's victory.

I will never take an unfair advantage in order to win.

I will always abide by the rules of the game—on the diamond as well as in my daily life.

I will always conduct myself as a true sportsman—on and off the playing field.

I will always strive for the good of the entire team rather than for my own glory.

I will never gloat in victory or pity myself in defe
Mack's last three seasons in the National League were as a player-manager with the Pittsburgh Pirates from 1894 to 1896, with a 149–134 (.527) record. Fired on September 21, 1896, 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. He agreed to a salary of $3,000 (equivalent to $90,000 in 2019) and 25% of the club. He managed the Brewers for four seasons from 1897 to 1900, their best year coming in 1900, when they finished second. It was in Milwaukee that he first signed pitcher Rube Waddell, who would follow him to the big leagues.
In 1901 Mack became manager, treasurer and part owner of the new American League's Philadelphia Athletics. He managed the Athletics through the 1950 season, compiling a record of 3,582–3,814 (.484) when he retired at 87. Mack won nine pennants and appeared in eight World Series, winning five.
Mack's 50-year tenure as Athletics manager is the most ever for a coach or manager with the same team in North American professional sports, and has never been seriously threatened. A few college coaches had longer tenures: John Gagliardi was a head football coach from 1949 to 2012, ending with 60 seasons at Saint John's of Minnesota; Eddie Robinson was head football coach at Grambling State for 57 seasons, from 1941 (when it was known as the Louisiana Negro Normal and Industrial Institute) to 1997; and the upcoming 2018–19 season will be the 52nd for Herb Magee as head men's basketball coach of the institution now known as Jefferson (1967–present). Joe Paterno, with 62 seasons as a college football coach for the Penn State Nittany Lions also surpassed Mack, although Paterno was head coach in only 46 of those years. College football pioneer Amos Alonzo Stagg also surpassed Mack in overall tenure, though not in tenure for a single employer; he was a head coach for 55 seasons in all (1892–1946), with the first 41 at Chicago (1892–1932).
Mack was widely praised in the newspapers for his intelligent and innovative managing, which earned him the nickname "the Tall Tactician". He valued intelligence and "baseball smarts," always looking for educated players. (He traded away Shoeless Joe Jackson despite his talent because of his bad attitude and unintelligent play.) "Better than any other manager, Mack understood and promoted intelligence as an element of excellence." He wanted men who were self-directed, self-disciplined and self-motivated; his ideal player was Eddie Collins. According to baseball historian Bill James, Mack was well ahead of his time in having numerous college players on his teams. Several of his players went on to become well-respected college coaches. Jack Coombs, the ace of Mack's 1910-11 champions, became the longtime coach at Duke. Andy Coakley, who won 20 games for Mack's 1905 pennant winners, coached for over 30 years at Columbia, where he was the college coach for Lou Gehrig. Dick Siebert, longtime coach at Minnesota, played for Mack from 1938 to 1945. James believed that Mack's influence on the game, as great as it was, would have been even greater had the college game been more popular during the 1920s and 1930s, when Mack was at his peak.
According to James, Mack looked for seven things in his players--"physical ability, intelligence, courage, disposition, will power, general alertness and personal habits."
As a result of Mack's striving to have his players become better people as well as baseball players, he created a Code of Conduct following the 1916 season:
I will always play the game to the best of my ability.
I will always play to win, but if I lose, I will not look for an excuse to detract from my opponent's victory.
I will never take an unfair advantage in order to win.
I will always abide by the rules of the game—on the diamond as well as in my daily life.
I will always conduct myself as a true sportsman—on and off the playing field.
I will always strive for the good of the entire team rather than for my own glory.
I will never gloat in victory or pity myself in defe
Connie Mack