In 1994, Idelson also served as assistant Vice President and senior press officer for the 1994 World Cup organizing committee.

[2] Idelson joined the Baseball Hall of Fame on September 26, 1994, as director of public relations and promotions.

[4] On February 4, 2019 Idelson announced he would leave the Hall of Fame presidency on July 21, following the 2019 induction ceremony.

[5] After his successor Tim Mead stepped down in May 2021, he returned as "interim president" through the 2021 induction ceremony on September 8 of that year.

[6] Idelson serves on the Advisory Council of the Harlem branch of Reviving Baseball in Inner Cities, Board of Directors of the Professional Baseball Scouts Foundation, and on the Board of Directors of the Otsego County chapter of the international program Girls on the Run.