Lenny Sirkes was a thug hired by campaign manager and real estate broker Jeff Jeffers to scare people out of part of Brooklyn so he could buy the land cheaply and build a shopping centre. Donning an armoured suit Lenny became the Lone Shark and started doing the job he was hired for. The Lone Shark (often misunderstood by his enemies who thought he was the Loan Shark) ended up fighting Luke Cage and his wife Jessica Jones and was quickly defeated.
After his arrest Lone Shark gave up his employer to the NYPD for a reduced prison sentence.
Despite his Shark like appearance the Lone Shark got all his powers from an armoured suit, This granted him strength beyond a normal human's ability and he had some skill as a brawler.