Jack Sharkey (born Joseph Paul Zukauskas, Lithuanian: Juozas Povilas Žukauskas, October 26, 1902 – August 17, 1994) was a Lithuanian-American boxer who held the NYSAC, NBA, and The Ring heavyweight titles from 1932 to 1933.

That put him in the ring on July 21, 1927, with his idol Dempsey, the winner to meet heavyweight champion Gene Tunney for the title.

In 1928 Sharkey fought heavyweight contender Tom Heeney to a draw and defeated former light-heavyweight champion Jack Delaney.

"[2] In fact Bill Carey, president of Madison Square Garden saved the day by appointing Jack Dempsey himself to the task.

Between leasing the Carl Fisher mansion on Miami Beach as well as the George Washington Hotel, the latter of which was equipped for the press with a 24-hour bar, the Sharkey-Stribling fight at the old Flamingo Park drew 40,000 fans, including 423 writers, and did $405,000 at the box office, an amount unsurpassed in the South until television receipts for Clay vs. Liston in 1964 managed a richer gate.

On June 21, 1932, at the Madison Square Garden Bowl in Long Island City, New York, Sharkey defeated Schmeling in a controversial split decision to win the championship.

In recent years, with the proliferation of European-born world heavyweight champions, fighters such as Chris Byrd and Hasim Rahman have also won and lost their championships against European opposition.