Helped form a cartel in order to control global business using lethal carbon disulfide 
Falsely posed as the Ashton family heir
Conspired with Jerry Jacks to gain access to ELQ by kidnapping Luke Spencer and replacing him with an imposter [revealed Nov 2014]
In 1988, Lord Larry docked his deeply-in-debt yacht, the Aphrodite, in Port Charles. He believed that the only way he could get his fortune back was to locate a long-lost Chinese civilization with the help of a key dubbed the Dragon Bone. In order to find the civilization, Larry needed more than just the Dragon Bone; he also needed an emerald and a map. He was also being followed by the villainous Domino who wanted the Dragon Bone. Domino, though, wasn't the one that Larry needed to be worried about. Tracy Quartermaine, Larry's ex-wife, also wanted to get rich and blackmailed Larry into giving her and their son, Ned, a share of any profits he made from the quest. If Larry refused, Tracy said that she would reveal that Larry wasn't the true Ashton heir -- but rather an impostor!
The Dragon Bone was buried by Robert Scorpio's dog Friday, and the quest fizzled. Still in debt, Larry left Port Charles with his new wife, Arielle. Larry soon after lost his title when a drifter, Charlie Prince, turned out to be the real Ashton heir.
In 1991, Larry returned alone to Port Charles and formed a cartel with Harlan Barrett, Leopold Taub, and Cesar Faison in order to control global business of carbon disulfide, a toxic substance manufactured at a Port Charles cannery. To achieve their goals, the cartel forced ELQ CEO Paul Hornsby to marry Tracy Quartermaine and take control of her ELQ stock. The trio ordered Paul to kill Tracy if necessary. The cartel was busted up on Founder's Day by the Port Charles Police Department and all traces of the toxic substance were destroyed.
Several years later, Larry returned to Port Charles and was reunited with his son Ned and his former wife Tracy courtesy of Jerry Jacks. Tracy had brokered a deal with Jerry in which he would return her husband in exchange for stock in ELQ. Tracy had expected Jerry to deliver her current husband Luke Spencer but instead he brought Larry to her. Neither Ned nor Tracy were thrilled with Larry’s return but Larry made the best of the unexpected family reunion and enjoyed the liquor supply. He also secretly updated Jerry with information about the Quartermaine family and ELQ.