Dan Boyle played Tier II Junior A hockey with the Gloucester Rangers before accepting a scholarship at the University of Miami-Ohio in 1994-95 where he scored 26 points as a freshman in the NCAA. After scoring 27 points the following year, he then scored 11 goals and 54 points in 1996-97 and was subsequently named both a CCHA First Team All-Star and a NCAA West First Team All-American. In 1997-98, Boyle scored 14 goals and 40 points and was again named both a CCHA First Team All-Star and a NCAA West First Team All-American.
On March 30, 1998, Boyle signed a free agent contract with the Florida Panthers. In that 1998-99 campaign, Boyle began his pro career and scored 42 points in 53 games with the AHL's Kentucky Thoroughblades. He started in the mid-season AHL All-Star Game and was named an AHL Second Team All-Star and later that season made his NHL debut in a game against the St. Louis Blues.
In 2000-01, Boyle earned a full-time roster spot with the Panthers, appearing in 69 games, scoring four goals and 22 points. Boyle would subsequently be dealt to the Tampa Bay Lightning where he has been quarterbacking the power play and been an offensive force from the back end.
Comming off a career year offensively in 2002-03 with 53 points (13-40-53), Boyle was instrumental in the club's run to the 2004 Stanley Cup title and was a key contributor in Canada's silver medal performance at the 2005 World Championship.
The puck-moving defenceman had a career year in 2006-07, appearing in 82 games and tallying 20 goals, 43 assists for 63 points. Mid-way through the following season, he signed a multi-year contract with the Tampa Bay Lightning.
In his first year of his new contract with Tampa, Boyle was hit by a skate when it slipped off a hook in the dressing room after a pre-season game. The freak accident split three tendons in his wrist, and Boyle would only appear in 37 games that season. The club suffered all season long and Boyle was asked to waive his no-trade clause, which he did, allowing a trade to the San Jose Sharks.
Boyle played for the Sharks for six seasons, including two appearances in the 2011 and 2012 Western Conference Final. At the conclusion of the 2013-14 season and Boyle a pending free agent, the Sharks traded his rights to the New York Islanders for a fifth round draft pick.
Boyle did not sign with the Islanders, instead signing with their rival New York Rangers to a two year contract on July 1, 2014.
On the international stage, Boyle was part of the Canadian team that captured gold on home soil at the 2010 Olympic Winter Games in Vancouver.