Syd began work in the broadcast and advertising industries at the age of 13 as a part-time office boy for KFWB radio in Los Angeles. He worked his way up through the news, production, promotion, advertising, and sales departments to station manager At that time, KFWB was a music-news-sports format ranked 5th in the greater Southern California Market. In 1958, Syd introduced "Color Radio-Fabulous 40" to the Southern California listeners, which was the greatest advertising promotion campaign ever by a radio station. In only 5-weeks, KFWB became the number one radio station in Southern California.

Later in 1958, Yallen became Executive Vice-President of Continental International Productions, a syndicator of radio and television programs. Nine years later, Syd became the West Coast Regional manager for a broadcast barter company, Pepper and Tanner. In 1970, Syd established the west coast operations for the media buying service, Media Partners, headquartered in New York. When the partnership dissolved, Syd formed his present company, Inter/Media, now in its thirtieth year.

In addition to his corporate financial and operation duties, Syd co-manages I/M key accounts as well as heads new business development.

Syd has a Bachelor of Science degree in advertising and marketing from the University of Southern California.