Richmond was drafted by the Carolina Hurricanes with the first pick in the second round in the 2003 NHL Entry Draft, and signed a three-year contract with Carolina on September 15, 2004. Richmond's first professional season was with the Lowell Lock Monsters of the American Hockey League in 2004–05, where Richmond scored four goals and had nine assists in 63 games. In the 2005–06 season, Richmond split time between Lowell and Carolina, appearing in ten games for the Hurricanes and tallying one assist, and was named to the AHL Planet USA All-Star Team. On January 20, 2006, Richmond was traded by the Hurricanes to the Chicago Blackhawks for Anton Babchuk, and was assigned to the Norfolk Admirals of the AHL. . On July 17, 2008, Richmond was traded to the Pittsburgh Penguins in exchange for Tim Brent. In the 2008–09 season, Richmond was assigned to Pittsburgh affiliate, the Wilkes-Barre/Scranton Penguins. Richmond played in 55 games with the Penguins before he was traded to the St. Louis Blues in exchange for Andy Wozniewski on March 4, 2009. On July 20, 2009, Richmond re-signed to a one-year contract with the Blues. Danny started the 2009–10 season with the Rivermen and played in 54 games before he was traded along with Hannu Toivonen, back to the Blackhawks, for Joe Fallon on March 1, 2010. On June 11, 2010 Richmond was an honorary guest in the Chicago Blackhawks Stanley Cup parade through Chicago. On September 30, 2010 Richmond received a Stanley Cup ring along with other Blackhawk players and staff at a private ceremony. On July 3, 2011, Richmond signed a one-year contract with the Washington Capitals organization. Assigned to AHL affiliate, the Hershey Bears for the 2011–12 season, Richmond played in only 24 games before he was traded by the Capitals to the Colorado Avalanche in exchange for Mike Carman on February 2, 2012. He was immediately assigned to AHL affiliate, the Lake Erie Monsters, where Richmond was credited in helping the Monsters in a late season push by scoring 7 points in 23 games. Unable to reach the playoffs with the Monsters, Richmond signed before free agency in North America to a one-year contract with Finnish team Lahti Pelicans of the SM-liiga on May 23, 2012. In the 2012–13 season, Richmond was leading the lowly Pelicans from the Blueline with 18 points in 39 games, before he was released from his contract and signed for the remainder of the season with European club, EC Red Bull Salzburg of the Austrian Hockey League, on January 27, 2013. After helping Salzburg reach the EBEL semi-finals, Richmond left as a free agent and opted to remain in Europe in signing a one-year contract with German club, EHC München of the DEL, on June 17, 2013. On June 19, 2014, Richmond transferred from Munich to rivals Adler Mannheim, agreeing to a two-year deal. In his first season with the Adler Mannheim, Richmond won the DEL championship, defeating Ingolstadt in 6 games. Richmond led all defenders in points for the Adler with 8 goals and 32 assists After three seasons with Mannheim, Richmond left as a free agent to sign a two-year deal with Eisbären Berlin on May 31, 2017.
