Ikenaga was one of the top pitchers in Nippon Professional Baseball before a scandal derailed his career at age 23.

He led the PL in wins, complete games (19), shutouts (6) and innings pitched (335-1/3).

The 1969 season saw Ikenaga post an 18–11 record and a 2.57 ERA, finishing 3rd in the league in wins.

On April 1 of that year, disgraced former Lions pitcher Masayuki Nagayasu gave an exclusive tape-recorded interview to the Shūkan Post newspaper that revealed other players on his former team were also involved in game-fixing during the 1969 season.

[6] The character Hidehiko Hayakawa in the 1998 anime series Princess Nine is based on Ikenaga.