- "You rough up my employees, that hurts my professional reputation. That's all any businessmen has."
- ―Len Sirkes
Sirkes worked as a loan shark in New York City, working under the rules that if he was not paid back in full, then anyone who had made a debt with him would be in danger. Sirkes made a deal with Antoine Grier; however, Grier soon disappeared with his money.
Hunting Antoine Grier
While looking for Antoine Grier, Sirkes' men were beaten up by Luke Cage, who was also looking for Grier. The next day Sirkes accompanied his men to search Grier's apartment and found Cage with Jessica Jones just as they were leaving. After a brief scuffle, Sirkes and Cage confronted each other and worked out a deal to join forces in searching for Grier, as Sirkes made it clear that he had not kidnapped him as he merely wanted his money back as it had been agreed by himself and Grier earlier.
By the next day, Sirkes and his men followed Cage and Jones to an abandoned warehouse where Grier had used Sirkes' money to grow marijuana in an attempt to start a drug dealing business with Victor. Once Jones reappeared with Grier in hand, Sirkes revealed himself and demanded that she hand over the boy to him; Jones refused and instead offered to hand over Grier's stockpile of marijuana in exchange for allowing Grier to return home. Sirkes insisted that he was unwilling to renegotiate their deal.
Sirkes' men attacked Jones but she quickly proved herself to be vastly stronger than they had anticipated. Cage soon joined the fight and as they fought Sirkes' men, Sirkes himself went after Grier, who was hiding under a table. Cage attempted to defend Grier and fought Sirkes one on one while Jones and Grier made their escape. Sirkes managed to overpower Cage and put him in a headlock while his men beat him; however Cage quickly regained the upper hand and defeated them all with ease.
- Expert Combatant: Sirkes proved himself to be a highly skilled brawler while fighting Luke Cage, coming close to subduing him when he got Cage into a tight headlock. However Cage's enhanced strength and unbreakable skin allowed him to defeat Sirkes and his henchmen eventually.
- In the comics, Lenny Sirkes was hired to create havoc in the streets of Brooklyn when Luke Cage was running for president of the Borough. He was defeated by Cage and his wife Jessica Jones, and confessed that he had been hired by one of Cage's rivals in the election.