Mark McGwire first entered the Oakland Coliseum clubhouse in August 1986 as a tall, broad-shouldered first baseman, swiftly changing the competitive dynamics of the American League. While his legacy is often linked to his record-breaking single-season home run chase in St. Louis, it was in the East Bay that he truly became a cultural icon. Alongside Jose Canseco, as part of the legendary "Bash Brothers," McGwire was the key offensive force of a team that dominated the late 1980s.

Following an 18-game debut in 1986, McGwire had a groundbreaking breakthrough in the 1987 season, setting a new major league record with 49 home runs, the most in the league. This outstanding achievement earned him the American League Rookie of the Year Award by unanimous vote, establishing the Athletics as a powerful, high-energy force in the lineup. His performance demonstrated that this was not a one-time event, as he followed up with three straight 30-homer seasons, helping Oakland win three consecutive American League pennants and successfully sweeping San Francisco in the 1989 World Series.

Although he received a Gold Glove for his defense in 1990 and hit 42 home runs in 1992, persistent heel and back injuries greatly limited his playing time, causing him to miss most of the 1993 and 1994 seasons. Once he was fully healthy again, his hitting power returned strongly. In 1996, he achieved a career-high by leading Major League Baseball with 52 home runs and posted a league-best .730 slugging percentage, showcasing his powerful hitting when in top form.

As McGwire neared free agency and the Athletics, in the midst of a rebuild, looked to the future, the front office faced a tough choice: trading the franchise legend to the St. Louis Cardinals in late July 1997 for three pitchers. During his time with Oakland, McGwire hit 363 home runs and achieved a .551 slugging percentage. He was also selected as an All-Star nine times while with the team. In 2019, Oakland inducted him into their Hall of Fame.

Reggie Jackson joined the organization in 1967, bringing incredible talent right from the start. He made his debut during the team’s last days in Kansas City and quickly became the heart of the lively "Swingin' A's" era in Oakland. Famous for his powerful, corkscrew swing that either sent the ball soaring for a home run or led to a strikeout, Reggie was truly one of the most captivating personalities in baseball.

Reggie Jackson came up with the A’s when they were still in Kansas City (1967), and he would become a starter the following year when the franchise relocated to Oakland.  That year would show precisely what everyone should forever expect from Jackson.  He went deep 29 times and led the AL in Strikeouts, but he was always a must-watch at bat.

In 1968, during the franchise's first year in Oakland, Jackson achieved a landmark by hitting 29 home runs, marking the arrival of a new kind of superstar who was not only a talented athlete but also a captivating showman. He continued to soar in 1969, delivering an impressive first-half performance that had him on track to challenge the all-time home run record, and he finished the year with 47 home runs and 118 RBIs.

Between 1970 and 1972, Jackson smoothly transitioned from a promising young slugger to a strategic leader guiding a rising powerhouse. Though he missed part of the 1972 postseason due to a high-stakes injury from stealing home in the ALCS, his outstanding regular-season performance, culminating in 25 home runs and 80 RBIs, was the key reason the Athletics made it to the Fall Classic and began their championship journey. By 1973, he had firmly established himself as a top run-producer, blending impressive power with a refined eye for drawing walks, paving the way for his unanimous MVP season.

Jackson achieved his peak in Oakland in 1973, giving us a season that still stands as a proud record for the franchise. He topped the American League in home runs (32), RBIs (117), and slugging percentage (.531), earning him the well-deserved title of American League MVP, chosen unanimously. Following this incredible season, he shone brightly in the playoffs, guiding Oakland to back-to-back championships and earning World Series MVP honors after hitting .310 and smashing a crucial home run in Game 7. He was a key figure in a team that celebrated a historic "three-peat" from 1972 to 1974, showing that his athletic talent was at its best when a championship was at stake.

His tenure in Oakland would end when he was due to become a Free Agent, and the A's Owner, Charlie Finley, arranged a trade to the Baltimore Orioles, believing he could not afford to sign him.  Jackson’s overall numbers with the Athletics would see him blast 269 Home Runs with a .496 Slugging Percentage.

Jackson would enter the Baseball Hall of Fame in 1993, and in 2009, his number 9 was retired by the team.  When the Athletics created their own Hall of Fame in 2018, he was inducted into the first class.

George Edward “Rube” Waddell arrived in Philadelphia in June 1902 under the patient, paternal watch of manager Connie Mack, who had previously managed the brilliant left-hander in the minor leagues. The Athletics were well aware of his reputation as an unpredictable eccentric, but Mack also recognized that beneath the erratic behavior lived a southpaw with unparalleled talent.

His time in Philadelphia was marked by an extraordinary ability to strike out batters, even in an era when contact was prioritized. Waddell set a historic standard by leading the American League in strikeouts during all six of his seasons with the team, including a remarkable 349-strikeout season in 1904 that remained a modern major league record for over sixty years. The 1905 season was his peak, as he achieved the rare AL pitching Triple Crown by leading the league in wins (27), strikeouts (287), and posting a 1.48 ERA. He was a dominant force on the mound, winning at least 20 games in his first four seasons with the team and leading the league in FIP four times.

His extraordinary talent was consistently overshadowed by a chaotic off-field life that often challenged the organization. Waddell's lack of emotional maturity, combined with a serious struggle with alcoholism, frequently distracted from his brilliance; he was known to abandon his team to chase fire engines, play marbles with kids under the stands, or go fishing unexpectedly. The conflict reached a critical point during the 1905 pennant race. After nearly single-handedly leading the Athletics to the World Series, he was sidelined for the entire Fall Classic due to a strange shoulder injury from a locker-room scuffle over a teammate's straw hat, fueling rumors that gamblers had paid him to sit out.

By the end of the 1907 campaign, his high-maintenance lifestyle and deteriorating relationships with his teammates forced Connie Mack’s hand. The Athletics sold the veteran star to the St. Louis Browns before the 1908 season. His personal demons quickly caught up to him, and he was out of the major leagues by 1910. He spent his final years drifting through the minors before his health collapsed, and he tragically passed away at just 37 from complications of tuberculosis and pneumonia.

With the Athletics, Waddell had a 131-82 record, 1,576 strikeouts, and a brilliant 1.97 ERA. Waddell was chosen for the Baseball Hall of Fame in 1946, and forty years later, his name was etched on the Philadelphia Baseball Wall of Fame.  The Athletics would also select Waddell for their franchise Hall of Fame in 2021.

In 1906, Eddie Collins arrived in Philadelphia as a collegiate standout from Columbia University, signing under a local alias to protect his amateur eligibility.  By 1909, he had emerged as the tactical brain of Connie Mack’s "$100,000 Infield," a second baseman whose mental acuity was matched only by his physical speed.

1909 was his first full season as a professional athlete, and he made the most of it. Collins achieved a significant milestone by batting .347 and stealing 63 bases. He reached an even more exceptional level in 1910, leading the American League with a career-high 81 stolen bases, becoming the first player in the history of the sport to surpass the 80-steal threshold. He contributed the dynamic energy that propelled the Athletics to three World Series championships in four years (1910, 1911, and 1913), establishing himself as a prominent figure of the Deadball Era, capable of influencing the game's tempo from the basepaths.

In 1914, Collins achieved an extraordinary level of individual recognition by producing an exceptional season that earned him the American League Most Valuable Player (MVP) Award. He demonstrated complete mastery of the game by leading the league in runs scored (122) for the third consecutive year and batting .344, thereby guiding the Athletics to their fourth pennant in five seasons. Nevertheless, the chapter in Philadelphia approached a pivotal juncture in 1915; amidst the imminent threat posed by the Federal League’s lucrative contracts, Connie Mack executed a significant transaction, transferring Collins to the Chicago White Sox for the sum of $50,000.

This would not be the end of Collins in Philadelphia.

After spending twelve productive seasons in Chicago, Collins’ return to Philadelphia in 1927 was a localized homecoming that brought his career full circle. Despite being 40 years old, he remained a sought-after professional mainstay, and he chose to reunite with Connie Mack to serve as a veteran player-coach for a rising Athletics squad. While he operated primarily as a tactical reserve, his localized value to the clubhouse was immeasurable as he mentored the next generation of Athletics legends. He reached a historic plateau of team success by serving as a professional mainstay on the 1929 and 1930 World Series championship rosters, making him the only player in franchise history to secure five championship rings with the team. He finalized his playing career after the 1930 season, departing as the only player in MLB history to spend at least 12 seasons with two different franchises.

As an Athletic, Collins compiled 1,308 hits, 337 stolen bases, and a .331 batting average.  He was inducted into the Baseball Hall of Fame in 1939 and the Philadelphia Baseball Wall of Fame in 1987.  The Athletics would also induct Collins into their franchise Hall of Fame in 2021.