He was graduated from the City University of Hong Kong before he ran in the 1999 District Council election in Tai Yuen in as the youngest candidate in the election for the Democratic Party, where he lost to veteran Cheng Chun-ping. He went to study abroad at the University of Hull in Social Policy.
In the 2003 District Council election, he ran again in Yee Fu and won a seat in the Tai Po District Council. He was re-elected in 2007, 2011 and 2015. He ran in the 2008 Legislative Council election in New Territories East on Andrew Cheng's ticket in which Cheng successfully retook his seat.
He was considered as the reformist faction in the Democratic Party. In the 2008 party leadership election, Yam ran for the central committee with other reformist faction headed by Andrew Cheng who challenged the vice-chairman post. The reformist ticket was largely defeated with Yam being the only reformist elected.[1]
In the 2012 constitutional reform package in which the Democratic Party made a compromise with the Beijing authorities, Yam quit the party with other reformists including Gary Fan and formed the Neo Democrats in which he became one of its convenor. In the 2012 Legislative Council election, he ran on Gary Fan's nine-man ticket in New Territories East, on the second place, and successfully gained a seat for the Neo Democrats with around 28,000 votes.
In the 2015 District Council election, he received the highest votes in the election, taking 4,148 votes in total.[2] He was on Gary Fan's ticket in the 2016 Legislative Council election again. Despite an increase in the number of votes, Fan failed to win the re-election.
