He then spent several years in Europe, playing in the Dutch Eredivisie with Heerenveen, German Bundesliga with Borussia Mönchengladbach, English Premier League with Aston Villa, and Italian Serie A with both Chievo and Roma.

[3] Michael spent his teenage years in Palatine, Illinois while his father coached the Chicago Fire of Major League Soccer (MLS), and he grew up playing for Sockers FC, who went to the 2002 National Championships and finished third.

Just weeks after his father was fired as the club's coach, he headed in his first professional goal in a victory over Chivas USA on the last day of the 2005 season, sending the team to the playoffs.

In January 2006, Bradley became the youngest MLS player to ever be sold when he was transferred to Heerenveen for $250,000 and a portion of any sell-on fee[5] His first start for the Dutch club came on April 16, 2006, in a match against AZ.

On November 15, 2008, Bradley scored his first goal for Mönchengladbach against Bundesliga powerhouse Bayern Munich with an eighty-first minute equalizing header.

On January 30, 2011, Aston Villa of the Premier League confirmed via their official website that they were in talks to sign Bradley on a loan deal until the end of the 2010–11 season.

[14][15] The following day, he made his debut for Roma as a starter in a 2–1 pre-season victory against Austrian Bundesliga club Rapid Wien, going head-to-head with fellow U.S. international Terrence Boyd.

"[19] On May 26 of that year, Bradley started in midfield for Roma as the club fell 1–0 to Rome rivals Lazio in the final of the Coppa Italia.

[23] Bradley made his debut with Toronto in their season opener at Seattle Sounders FC on March 15, 2014, the game ended in a 2–1 away victory with both goals coming from newly acquired Jermain Defoe.

[33] On September 30, 2017, Bradley won his first Supporters' Shield with a 4–2 home win over New York Red Bulls, to clinch top of the league with the most points that season.

[34] On December 9, 2017, Bradley helped Toronto defeat Seattle 2–0 in the 2017 MLS Cup at BMO Field, to lift the title for the first time in the club's history, and complete an unprecedented domestic treble.

[50] Bradley was later reported to have confronted referee Jorge Larrionda following the match, resulting in him receiving an additional three-match suspension to be served during the 2009 Gold Cup.

At the 2011 Gold Cup, Bradley featured in each game, forming a new midfield partnership with Jermaine Jones, and scored the opening goal in the final against Mexico, though the Americans went on to lose 4–2.

[53] Following the Gold Cup loss, Bob Bradley was fired as national team coach and replaced by Jürgen Klinsmann, under whom Michael remained a key starter in midfield.

[54] After Clint Dempsey had his captaincy removed as punishment for a controversial incident with a referee, Klinsmann named Bradley the national team's new permanent captain ahead of the 2015 Gold Cup.

[57] Although not initially included in the final squad for the 2017 Gold Cup, Bradley would be one of six alternate players later added to the U.S. roster for the knockout stage.

[58] Bradley went on to play every minute of the United States' three knockout games, lifting his second Gold Cup title after they defeated Jamaica in the final.

[60] Bradley was a mainstay of the United States' 2018 World Cup qualification campaign, and would score the opener in a crucial match against Mexico at the Azteca Stadium on June 11, 2017, chipping an effort over goalkeeper Guillermo Ochoa from roughly 40 yards out to help the Americans earn a 1–1 draw.

[62] Bradley was one of several senior players to receive extensive criticism from American media and fans, citing his subpar performances and a lack of leadership shown as captain of the team.

[63][64] After returning to club duty with Toronto FC, both Bradley and fellow national teammate Jozy Altidore would routinely be booed and jeered by opposition fans when playing MLS games in American stadiums.

[74] Bradley's tenacity, ball-winning abilities, energy, tactical intelligence, and positional sense enabled him to recover the ball and quickly transition from defense to attack by making forward runs, while his vision and range of passing allowed him to dictate the tempo of his team's play in midfield or create goalscoring opportunities after retrieving possession.

[4][80] Bradley's father, Bob, managed sides including the United States men's national team and Toronto FC for a brief period while his son was captain of the club.

Scott Bradley, the younger brother of Bob and uncle of Michael, played as a catcher in Major League Baseball, primarily for the Seattle Mariners, and served as long-time coach of the Princeton Tigers.