Luke Richardson was selected seventh overall by the Toronto Maple Leafs in the 1987 NHL Entry Draft after two successful seasons with the Peterborough Petes of the OHL. Midway through his rookie NHL season, on January 6, 1988, Richardson was the victim of an infamous attack from Dino Ciccarelli of the Minnesota North Stars, who clubbed him over the head several times with his stick. Ciccarelli was later convicted of assault, serving one day in jail and paying a fine of $1000 (Canadian). However, the assault had no discernible effects on the play of Richardson. He remained a regular on the Toronto blueline until 1991 when he was involved in a blockbuster trade, moving to the Edmonton Oilers along with Vincent Damphousse, Scott Thornton, Peter Ing, future considerations, and cash in exchange for Grant Fuhr, Glenn Anderson and Craig Berube.
Though not a great point producer, Richardson developed a reputation as an aggressive, stay-at-home blueliner. He would be consistent in that regard during stops with the Oilers, the Philadelphia Flyers and the Columbus Blue Jackets. It was with the Flyers that Richardson came the closest to a Stanley Cup appearance in 2000, when the Flyers lost 4–3 in the Eastern Conference Finals to the New Jersey Devils.
During the 2005–06 season, his last as captain of the Blue Jackets, Luke was traded back to Toronto on March 8, 2006.
Richardson continued playing in the 2006–07 season when he signed a one-year contract with the Tampa Bay Lightning, playing in 27 games and registering 3 assists and 16 penalty minutes. Richardson was a healthy scratch by the end of the 2006–07 season and playoffs, and became an unrestricted free agent that summer.
On August 7, 2007, Richardson signed a one-year, $500,000 two-way contract with his hometown Ottawa Senators, amid the speculation that he would soon announce his retirement from the NHL. On February 15, 2008, Richardson was named the Senators' nominee for the Bill Masterton Memorial Trophy, though the award eventually went to Jason Blake of the Toronto Maple Leafs.
On September 27, 2008, Richardson re-signed with Ottawa to a one-year, two-way contract. During the 2008–09 season and, being used primarily as a reserve defenceman, Richardson announced his retirement as a player on November 27, 2008, having played in just two games that season, with the intention of pursuing a coaching career. He was hired as an assistant coach by the Senators later that season.
Richardson began his coaching career during the 2009–10 NHL season behind the bench of the Ottawa Senators, as an Assistant Coach to Head Coach Cory Clouston. During the two years under Clouston, the Senators struggled to establish itself as a playoff contender, enduring setbacks caused by injuries, changes from the Senators' usual defensive strategy to an unsuccessful offensive play style, and communication issues between Clouston and the Senators roster (notable by the departure of star player Dany Heatley in the year prior to Richardson's first year). Clouston was fired by GM Bryan Murray in Richardson's second year. He served under new Head Coach Paul MacLean during the 2011-12 NHL season in his last year as Ottawa Senators' Assistant Coach. During his time behind the Senators' bench, the Senators posted a 117-103-26 record over 3 seasons, making the playoffs twice but never progressing past the first round, losing to the Pittsburgh Penguins in 6 games, and falling one game short to the New York Rangers.
After three seasons as an assistant coach in Ottawa, Richardson joined the Binghamton Senators, Ottawa's top minor league affiliate, as head coach. During his rookie season as head coach, Richardson led an inexperienced Binghamton team to a 44–24–1–7 record, finishing fourth in the AHL's Eastern Conference. He was named coach of the AHL Eastern Conference all-star team in 2012–13 after guiding the Senators to the conference's best record at the all-star break. The Senators' organization subsequently rewarded Richardson with a contract extension through the 2014–15 season.
Richardson signed another one-year contract for 2015–16. Richardson turned down an assistant position with Ottawa, seeking to stay as head coach of Binghamton, with an end to pursuing a future NHL head coaching opportunity. At the end of the season, after the Senators had fired Dave Cameron, the Ottawa head coach, Richardson decided to leave the Senators' organization to pursue other opportunities. Richardson had asked to be considered for the Ottawa position but was turned down by new general manager Pierre Dorion.
On May 18, 2017, Richardson was hired by the New York Islanders as an assistant coach.
On October 7, 2016, he was named assistant coach for Team Canada at the Deutschland-Cup. In December 2016, he served as head coach of Team Canada at the Spengler Cup in Switzerland and led Canada to its 14th title at the prestigious event.
On November 13, 2010, his daughter Daron died from suicide at the Richardson family home in Ottawa, Ontario. On November 18, 2010, 5,600 mourners attended a celebration of life ceremony for Daron at Scotiabank Place. Of note, the Philadelphia Flyers (one of Luke Richardson's former teams) held a moment of silence for Daron before their game against the Senators on November 15.
On February 2, 2011, Richardson and his family decided to raise awareness of teen suicide and depression in hopes of preventing further tragedies like this from occurring. Richardson, the Royal Ottawa Foundation for Mental Health, the Sens Foundation, and the Ottawa Senators announced the creation of a program to inspire conversations about youth mental health. Called Do it for Daron, the hope was to honour her memory while raising money to prevent teenage suicide.
During the 2011–12 Canada women's national ice hockey team season, his daughter Morgan was a member of the Canadian National Under-18 team that participated in a three-game series vs. the USA in August 2011.
He is the uncle of the NHL hockey player, Jakob Chychrun.1999–2000: Pelle Lindbergh Memorial (Philadelphia Flyers)
Played for Team Canada in the 1987 World Junior Ice Hockey Championships.
Played for Team Canada in the 1994 Men's World Ice Hockey Championships.
Played for Team Canada in the 1999 Men's World Ice Hockey Championships.