Lalonde won his first four fights and then lost a six-round decision to Wilbert "Vampire" Johnson in March 1981.
In 1983, Lalonde won the Canadian Light Heavyweight Championship, knocking out Roddie McDonald in ten rounds.
He defeated McDonald even though he had a smashed middle knuckle on his right hand and was recovering from surgery on his left shoulder, which he first separated when he crashed into the boards while playing hockey in 1977.
To prepare for his fight with McDonald, he underwent an operation in which doctors inserted a pin to bind the joint, which severely restricted his ability to raise his left arm.
He and Atlas parted ways, and Lalonde hired Tommy Gallagher and Bobby Cassidy as his new trainers.
On November 27, 1987, Lalonde knocked out Eddie Davis in two rounds to win the vacant WBC Light Heavyweight Championship in Port of Spain, Trinidad and Tobago.
[1] On November 7, 1988, Lalonde fought Sugar Ray Leonard at Caesar's Palace in Las Vegas, Nevada.
[2] After Leonard vacated the WBC Light Heavyweight Championship, Lalonde was scheduled to fight Dennis Andries for the title on June 24, 1989 in Atlantic City, New Jersey.
After four straight wins, he fought Bobby Czyz for the WBA Cruiserweight Championship on May 9, 1992 in Las Vegas.
Lalonde got up and survived the round, but for the rest of the fight, Czyz continued to come forward and land effectively with left jabs and hooks.
After three consecutive wins, Lalonde fought former two-division champion Virgil Hill in Winnipeg on July 7, 2003.
Hill controlled the fight, landing frequently with jabs and hooks while avoiding Lalonde's powerful right.
Lalonde is now aiming to help boxers live a healthier life in their golden years through his initiative "TKOOO" (Taking "K"are Of Our Own).
Its mission is to educate fighters on the benefits of natural and preventative medicine, including the reduction or elimination of the trauma induced by effects of combat sport.
[7] In 2004, Lalonde declared bankruptcy in B.C., owing $1.5 million to creditors, mostly linked to failed real estate ventures, and moved to Tamarindo in northwestern Costa Rica where he sold pre-construction lots in a new community.
Ten years later, about 30 investors hired a lawyer, hoping to recoup $3.5 million in a class-action lawsuit.
[8] In 1988, William Nack commented that Lalonde's "diet is chiefly vegetarian; he eschews all processed foods.