In medical school, Matthew, Leslie, and Thomas were best friends, known as “The Three Musketeers."
Matthew's career took a downward turn when his brother, Rupert, received a gunshot wound and came to his brother for help. Trying to shield him, Matthew did not follow procedure by preparing a report for the police. When the medical board learned of this, Dr. Thorne's medical license was revoked, and his business reputation was permanently damaged.
Matthew was reduced to working secretly for his brother's criminal organization, providing various illegal services to Rupert and his men off the books. Rupert tried to keep his brother happy by setting him up in an unofficial clinic, with his own staff, and various stolen pieces of advanced medical equipment. Inside, however, Matthew yearned for his old life back, and Rupert kept him on the hook with promises that he could provide that. Rupert Thorne claimed he could bribe, blackmail, and pull strings with the medical board to reinstate his brother's medical license, but he did not seem to be doing much to follow through on it.
When Rupert needed open heart surgery, he refused to be admitted to a hospital, where he would be vulnerable to his many enemies. He insisted that his brother do the surgery, promising that this time he would have his license reinstated, but Matthew said that the surgery was beyond his skills and that he couldn't do alone. He said that in order to succeed he would need the help of another doctor to assist him. To this end, Rupert Thorne allowed his brother to use some of thugs from his organization to kidnap the required specialist. Subsequently, Thorne's men and Doctor Thorne kidnapped Leslie Thompkins from her office. Leslie and Matthew successfully performed the surgery in Matt's "clinic."
Thorne had given orders that Leslie was to be eliminated after the job was done. Hearing this, Matthew renounced all loyalty to his brother. Matthew agreed to go along with the order, saying that it had to be done his way, inject her with poison which so as not to leave any traces of Rupert to the crime, which Rupert agreed was a fine idea. When one of Thorne's men escorted Dr. Tompkins to a room to have this done, Dr. Thorne injected him with the "poison" instead, which caused the goon to slump over. Dr. Thorne revealed the chemical was only a mild sedative and the man would wake up shortly. Matthew and Leslie quickly made their escape. They were pursued by Thorne's thugs, and nearly killed, but Batman managed to save them.
Matthew was then arrested as an accomplice to Rupert's gang. While he was awaiting trial, Bruce Wayne visited him in jail, offering to pay for a lawyer as well as trying to convince the judge to be lenient with him. Suspicious, Matthew was sure that Bruce wanted something in return. When Bruce admitted that he did, it was something Matthew could give happily: stories about his old friend, Thomas Wayne (Bruce's father).