He began umpiring while serving as an Army Special Services officer during World War II, and eventually worked his way up to the National League after stops in the Eastern Shore (1948), Interstate (1949), Western (1950–52) and Pacific Coast Leagues (1953–59).
He worked in the World Series in 1966 and 1972, serving as crew chief the second time, and in the All-Star Game in 1961 (second game), 1967 and 1975. He also officiated in the National League Championship Series in 1969 and 1973.
He is perhaps best remembered today for ordering an apparent Hank Aaron home run nullified on August 18, 1965 because Aaron stepped out of the batter's box when he made contact; the umpire had warned Aaron on the previous two pitches. As a result, Aaron's home run record eventually stood at 755, instead of 756.
Pelekoudas was also the first umpire to eject Gaylord Perry from a game for using an illegal greasy substance on the ball.
Pelekoudas umpired in six no-hitters in all, although was never behind the plate for any of them and was, also, an umpire for the first game ever held at Shea Stadium on April 4, 1964.
In the 1998 book Baseball's Golden Greeks by Diamantis Zervos, Jim Campanis describes a "Greek moment" in baseball when he was batting against Cincinnati Reds pitcher Milt Pappas, with Alex Grammas the third base coach and Pelekoudas calling balls and strikes behind the plate.
He had married Jane Papangellin on April 28, 1946, and they had a daughter and a son. His brother Perry was also an umpire, working in the minor leagues. His son Lee Pelekoudas worked in the Seattle Mariners organization for 30 years.
- National League 1968 Green Book, p. 26.
- "Obituaries". The Sporting News. 1985-01-07. p. 43.
- Dittmar, Joseph J. (1990). Baseball's Benchmark Boxscores. Jefferson, North Carolina: McFarland & Co. pp. 132–34. ISBN 0-89950-488-4.
- Coberly, Rich (1985). The No-Hit Hall of Fame: No-Hitters of the 20th Century. Newport Beach, California: Triple Play. p. 122. ISBN 0-934289-00-X.
- Coberly, p. 131.
- 1975 National League Green Book, p. 33.
- "Mariners' interim GM Lee Pelekoudas: A life in baseball". The Seattle Times. 2008-06-27. Retrieved 2018-06-14.