Amnon has been extremely active in public service. He has served on boards and committees of various organizations including, as Chairman of the East Jerusalem Development Company, from 1993 till 1999 and as Chairman of the board of directors of Tahal, then Israel's largest infrastructure and water planning company, from 1993 till 1996. He served on the board of directors of the National Youth Exchange Council from 1986 till 1989, and of the Betzalel Academy of Art and Design between 1991 and 1995.
Amnon was active in Israel's Labor Party and served as Chairman of the Labor Party High Tribunal from 2001 till 2008.
Amnon joined the firm in 1980 and became a partner in 1984. He clerked at the New York firm of Shea & Gould in 1981.