Dee ihe na-esote paragraf a - Horowitz bụ onye isi na US n'afọ ndị 1930 na 1940. Ọ bụ onye mmeri US Open na 1936, 1938, na 1943. N'afọ 1941, o meriri Samuel Reshevsky n'asọmpi U.S. Chess Championship (+0−3=13). O so n'Òtù Mba Amerịka n'egwuregwu Chess Olympiad anọ, n'afọ 1931, 1935, 1937, na 1950
Na egwuregwu egwuregwu egwuregwu redio ama ama nke United States na USSR na 1945, Horowitz meriri otu n'ime mmeri abụọ maka United States site na imeri GM Salo Flohr. O kewara "obere egwuregwu" ya nke egwuregwu abụọ megide Flohr, na mbipụta 1946 nke otu ihe ahụ, kewara obere egwuregwu ya megide Isaac Boleslavsky.