Jim Yeadon has been a gay activist since 1969. He was instrumental in framing the revised equal opportunities ordinance which extended protections against discrimination in housing and employment to gays. Considered an authority on municipal gay rights ordinances in the mid 1970s, at the time Yeadon felt Madison had one of the strongest.

In October 1976, Yeadon was elected as the first openly gay alderperson in Madison, and according to some accounts, only the third openly gay person elected for office in the country. Initially elected to complete the term of a resigned councilman, the 26 year old man was subsequently elected to a full term on the Madison City Council in April, 1977.

According to an article in late 1977, as a gay activist, Yeadon also was a binding force in the May 1977 "anti-Anita Bryant Bash" which attracted over 600 people to the UW's Memorial Union Great Hall in Madison. (At the time gays across the country were boycotting Anita Bryant for her anti-gay stands, and by extension, there was a wide-ranging boycott of orange juice, because the Florida Citrus Board, which used her as their spokesperson, refused to disassociate itself from her.)

Yeadon has practiced law since 1975, and began specializing in real estate law in about 1980. As of 2007, Yeadon continues to practice real estate law in Madison, as well as working part time for the State of Wisconsin.