After spending the winter working as a cell phone salesman for Telus in the Toronto area, he signed with the Milwaukee Brewers on March 4, 2008.
A 5–10 campaign with a 4.55 ERA for the Brevard County Manatees was followed by an offseason employment as a bartender at an East Side Mario's location in Hamilton, Ontario.

Used exclusively out of the bullpen in 2009, he improved to a combined 9–1 with the Manatees, Huntsville Stars and Nashville Sounds.
He was called up to the Brewers on September 7, and made his major league debut eight nights later as the last Brewers pitcher in a 13–7 loss to the Chicago Cubs at Wrigley Field.
He surrendered an earned run, a hit and three walks in one inning pitched.

Axford started 2010 in Nashville before being promoted by the Brewers on May 15.
With Trevor Hoffman struggling in save situations, Axford, despite having never been a closer in his career, was given the job, where he became a big success in the role and gained popularity with Brewer fans as he sported a handlebar mustache in many of his early appearances, evoking memories of legendary reliever Rollie Fingers.
Axford finished his first full season with an 8–2 record, a 2.48 ERA, pitched in 50 games, was 24 out of 27 in save attempts, and struck out 76 batters in 58 innings pitched.
He was named a relief pitcher on Baseball America's 2010 All-Rookie Team.

Axford went into 2011 as the Brewers closer and struggled early, blowing two saves in the first two weeks of the season, then went on to convert every single save opportunity the rest of the way.
In a game against the Chicago Cubs on July 27, Axford converted his 26th consecutive save opportunity, breaking Doug Jones's Brewers franchise record.
Axford was named DHL Delivery Man Award winner for the month of July 2011, in which he recorded 11 saves with a 2.57 ERA.
On September 24, he set the Brewers franchise record for most saves in a single season, saving his 45th against the Florida Marlins.
 For the season he led the National League in saves (46), and was second in games finished (63), pitching ​73 ²⁄₃ innings with 86 strikeouts and 59 hits while going 2–2 with a 1.95 ERA.
Axford was the first Brewers pitcher since Rollie Fingers to be a league leader in saves.
He continued his success in the 2011 postseason, appearing in 6 playoff games and racking up 3 saves and a 1.29 ERA while striking out 9 batters in 7 innings pitched.
Axford, however, blew his first save since the second week of the season in the decisive Game Five of the NLDS, but still got the win as the Brewers won in the 10th inning.
On October 28, Axford was named the recipient of the 2011 Robert Goulet Memorial Mustached American of the Year Award by the American Mustache Institute.
Recognition of Axford's success in 2011 continued into the offseason, where he was ninth overall in voting for the NL Cy Young Award and 17th overall for the NL MVP award.
He was nominated for and won several awards recognizing his success, including the NL Rolaids Relief Man (given to the league's best closer), and the Canadian Tip O'Neill Award (presented annually by the Canadian Baseball Hall of Fame to the Canadian-born player judged to have excelled in individual achievement and team contribution).
He shared the award with Joey Votto, the third time the Tip O'Neill has been shared.

Axford began 2012 with six straight saves, extending a streak to 49 consecutive save opportunities converted.
This was the fourth-longest streak in MLB history.
The streak ended on May 11, 2012, in a game against the Chicago Cubs.
As it turned out, Axford's wife began going into labor with the birth of his second child that night, and he was unavailable to comment after the game.
Instead, he left a handwritten note for journalists in his locker.
On July 16, Axford gave up three runs in the top of the ninth to blow a 2-0 lead.
Axford, however, was able to regain his control and was reinstated as the Brewers closer in the second half of the season.
He managed to rebound enough to finish the 2012 season with 35 saves, which was still good enough for 6th
After spending the winter working as a cell phone salesman for Telus in the Toronto area, he signed with the Milwaukee Brewers on March 4, 2008. A 5–10 campaign with a 4.55 ERA for the Brevard County Manatees was followed by an offseason employment as a bartender at an East Side Mario's location in Hamilton, Ontario.
Used exclusively out of the bullpen in 2009, he improved to a combined 9–1 with the Manatees, Huntsville Stars and Nashville Sounds. He was called up to the Brewers on September 7, and made his major league debut eight nights later as the last Brewers pitcher in a 13–7 loss to the Chicago Cubs at Wrigley Field. He surrendered an earned run, a hit and three walks in one inning pitched.
Axford started 2010 in Nashville before being promoted by the Brewers on May 15. With Trevor Hoffman struggling in save situations, Axford, despite having never been a closer in his career, was given the job, where he became a big success in the role and gained popularity with Brewer fans as he sported a handlebar mustache in many of his early appearances, evoking memories of legendary reliever Rollie Fingers. Axford finished his first full season with an 8–2 record, a 2.48 ERA, pitched in 50 games, was 24 out of 27 in save attempts, and struck out 76 batters in 58 innings pitched. He was named a relief pitcher on Baseball America's 2010 All-Rookie Team.
Axford went into 2011 as the Brewers closer and struggled early, blowing two saves in the first two weeks of the season, then went on to convert every single save opportunity the rest of the way. In a game against the Chicago Cubs on July 27, Axford converted his 26th consecutive save opportunity, breaking Doug Jones's Brewers franchise record. Axford was named DHL Delivery Man Award winner for the month of July 2011, in which he recorded 11 saves with a 2.57 ERA. On September 24, he set the Brewers franchise record for most saves in a single season, saving his 45th against the Florida Marlins.  For the season he led the National League in saves (46), and was second in games finished (63), pitching ​73 ²⁄₃ innings with 86 strikeouts and 59 hits while going 2–2 with a 1.95 ERA. Axford was the first Brewers pitcher since Rollie Fingers to be a league leader in saves. He continued his success in the 2011 postseason, appearing in 6 playoff games and racking up 3 saves and a 1.29 ERA while striking out 9 batters in 7 innings pitched. Axford, however, blew his first save since the second week of the season in the decisive Game Five of the NLDS, but still got the win as the Brewers won in the 10th inning. On October 28, Axford was named the recipient of the 2011 Robert Goulet Memorial Mustached American of the Year Award by the American Mustache Institute. Recognition of Axford's success in 2011 continued into the offseason, where he was ninth overall in voting for the NL Cy Young Award and 17th overall for the NL MVP award. He was nominated for and won several awards recognizing his success, including the NL Rolaids Relief Man (given to the league's best closer), and the Canadian Tip O'Neill Award (presented annually by the Canadian Baseball Hall of Fame to the Canadian-born player judged to have excelled in individual achievement and team contribution). He shared the award with Joey Votto, the third time the Tip O'Neill has been shared.
Axford began 2012 with six straight saves, extending a streak to 49 consecutive save opportunities converted. This was the fourth-longest streak in MLB history. The streak ended on May 11, 2012, in a game against the Chicago Cubs. As it turned out, Axford's wife began going into labor with the birth of his second child that night, and he was unavailable to comment after the game. Instead, he left a handwritten note for journalists in his locker. On July 16, Axford gave up three runs in the top of the ninth to blow a 2-0 lead. Axford, however, was able to regain his control and was reinstated as the Brewers closer in the second half of the season. He managed to rebound enough to finish the 2012 season with 35 saves, which was still good enough for 6th
John Axford