It was Muir who lead the way for American players to get involved in international play with the ICCF and he served as the secretary of the ICCF for the US. Muir was the founder of the United States Postal Chess Union, the organization that provided access for international postal play for members of CCLA, United States Chess Federation, American Postal Chess Tournaments, Knights Of the Square Table and The Chess Connection.
The APCT was one of the leading US postal clubs for about 35 years and when the organizers of the club, Helen and Jim Warren, announced their retirement in 2005 the club went out of existence after the last tournaments were completed.
NOST (Knights of the Square Table) was founded in 1960 by Robert Lauzon and Jim France as a postal organization with aim was to play in a less competitive atmosphere, in which friendship and conversation were more emphasized than winning. Over time, members also began playing Chess variants as well as Shogi. The club also included Checkers and Go. NOST lasted 43 years, closing down its website in 2003. This was because its members had aged or died and because the internet had begun to supplant postal chess.
The Chess Connection was a significant group with many strong players and that featured high prize fund tournaments and they published an outstanding magazine.
Muir won the Canadian Correspondence Chess Association Champion nine times: 1928, 1932, 1933, 1934, 1935, 1936, 1939, 1942, was the British Overseas CC Champion twice and, champion of the Illinois CCA 16 times. He also won nine ICCF Master Tournaments, qualified seven times for ICCF World Championship second-round play, and played on four Olympiad teams for the United States.
Muir was the first US player to defeat a USSR player (Atjashev) in ICCF competition The Walter Muir Memorial Invitational Correspondence Chess Tournament is named in his honor, and is supported by both the ICCF USA. and the Canadian Correspondence Chess Association.
Both of his parents were Canadian citizens. His father was a meat company executive whose job moved him to many cities around the world and Walter was born in Brooklyn, New York.
He surveyed the right-of-way between Albany, New York and New York City for the New York Power and Light Company between 1931-1932, but spent most of his life in Salem and Roanoke, Virginia. He was employed by General Electric for 46 years. He was married to Dorothy Saunders Muir for 65 years.
The Dorothy S. and Walter Muir Memorial Fund Established through Muir's estate. The fund supports the Roanoke Valley Chess Club, where was the president for some time, the Fintel Library at Roanoke College and the Western Virginia Foundation for the Arts and Sciences. The annual Walter Muir Chess Tournament is held in his honor.
Muir makes mincemeat of his opponent, Frank Valvo, in the following game. Valvo was the father of Michel Valvo. Frank was a prominent correspondence player of his day and in the 1950s and 1960s he played in many OTB events in New York state.