Arnold Sheldon Denker was born on February 20, 1914 in the Bronx.
Denker began playing chess as a high school freshman at Theodore Roosevelt High School. He learned chess by watching his older brothers play. He began playing against a neighbor, then against his neihbor's nephew, Irving Chernev.
In 1928, Denker joined the Manhattan Chess Club as a junior member.
In 1929, at the age of 15, Denker won the New York City individual interscholastic championship. He was captain of his high school team.
In his youth, Denker was a Golden Gloves boxing quarterfinalist and later a boxing manager.
In the 1930s, Denker graduated from New York University.
In 1936, Denker and Al Horowitz shared a room at the Lincoln Hotel managed by a fellow member of the Manhattan Chess Club (Chief Hall). They stayed without paying rent. During the day, Denker and Horowitz would hustle chess games for quarters. Whoever won the most during the day had to pay dinner.
In 1936, Denker took 2nd place at the US Open in Philadelphia.
In December 1936, Denker married Nina Simmons. Denker was introduced to Nina by violinist Max Rosen, a member of the Manhattan Chess Club.
In 1937, Denker got a job in a meat-packing company.
In August 1938, Denker won the New York State championship.
In 1940, Denker won the first of six championships of the Manhattan Chess Club.
In 1940, Denker played 100 opponents in 7.33 hours. The exhibition took place in Cleveland.
In 1941, Denker took 2nd-4th in the New York State Championship, won by Reuben Fine.
During World War II, he gave exhibitions at military bases and aboard aircraft carriers. He also was invited by the US government to help crack enemy codes.
In 1942, Denker took 3rd-4th place in the U.S. Chess Championship in New York. It was this tournament that the tournment director, L. Walter Stephens, mistakenly declared Denker's time had expired in round 6, when it was actually Reshevsky's time (he was looking at the clock backwards).
In May 1944, Denker won the U.S. Chess Championship. He scored 15 1/2 - 1 1/2 (14 wins, 0 losses, and 3 draws). This is the best result (91%) in US Chess Championship play except for Fischer's 100% record. Denker's 14 wins is the most in any US Chess Championship.
In September 1945, Denker played Botvinnik on top board in the US vs USSR Radio match. He lost both games.
In 1945/46 he took 3rd place at Hastings.
From May 4 to 18, 1946, Denker played and won the U.S. Chess Championship again. He defeated Herman Steiner in a match in Los Angeles with a 6-4 score. The prize fund was $5,000.
In August-September 1946 he took 10th-12th place as Groningen.
In 1946, Denker travelled to Moscow and played Smyslov in the US vs USSR match.
In 1947, Denker wrote "If You Must Play Chess."
In 1948, Denker now had two children and gave up full-time chess playing after playing at Mar del Plata. He took over his meat-packing business when the previous owner died.
In 1950, Denker was awarded the International Master title.
In 1970, Denker retired to Fort Lauderdale.
In 1971, Denker began playing competitive chess again.
In 1971, Denker tied for 7th place in the U.S. Open.
In 1981, Denker was made an honorary Grandmaster.
In 1981, Denker wrote "My Best Games of Chess 1929-1976."
In 1984, Denker started the Arnold Denker Tournament of High School Champions.
In 1988, Denker, age 74, lost a match against a Hitech computer. He became the first grandmaster to lose to a computer.
In 1992, Denker was inducted into the U.S. Chess Hall of Fame.
In 1993, he wife, Nina, died.
In 1995, Denker co-wrote with Larry Parr "The Bobby Fischer I Knew and other stories."
In 1995, Denker took 6th place in the U.S. Open.
In 2003, Denker was suffering from brain cancer.
In 2004, Denker was given the title of Dean of American Chess (Helms and Koltanowski were the previous title holders).
Denker died at his home in Fort Luaderdale, Florida on January 2, 2005. He had brain cancer. He was 90.