Hadley had played professionally in the Detroit Tigers organization and in the majors with the Kansas City A's and New York Yankees before signing with the Nankai Hawks in 1962. (Most notably he was included in the trade that sent Roger Maris from Kansas City to New York.) He made a splash in his debut with the Hawks as he became the fourth player and first foreigner to homer in his first at bat in NPB. He spent six seasons with the Hawks, hitting .260 with 131 home runs and 396 RBIs. His best season was 1963 when he hit .295 with 30 home runs and 84 RBIs and became the first foreign player elected to start in the All Star game. He helped the Hawks win the 1964 Nippon Series over the Hanshin Tigers with a walk-off home run to win Game Four. Amazingly he had a second walk-off Nippon Series home run when his two run shot beat the Yomiuri Giants in Game Five of the 1966 Series. He was the first foreign player to hit over 100 home runs in Japan. Nankai released him after the 1967 season and he retired from baseball. He spent the rest of his life running an insurance business in his hometown of Pocatello, Idaho. He passed away in 2005.
As I mentioned before, he has not had any "modern" Japanese baseball cards but I know of a couple from when he was a player. He appears in the Marukami "Bat On Right" menko sets from 1963 (JCM 14f) and 1964 (JCM 14g), the 1964 Marusan menko set (JCM 11) and the 1967 Kabaya-Leaf set. There may be others but this is all I could find (or are listed over at TradingCardDB.com). I have the two Marukami cards:
|1963 Marukami JCM 14f|
|1964 Marukami JCM 14g|