Many shows lay claim to be the first freeform radio program; the earliest is on KPFA-FM in Berkeley, California, DJ'd by John Leonard. WFMU is currently the longest-running freeform radio station in the United States. Jim Ladd of KLOS in Los Angeles, California is one of the most notable current freeform DJs. Tom Petty wrote a song about Jim Ladd called "The Last DJ". The only time Jim Ladd doesn't have complete control over what music is being played is when he turns control over to his faithful listeners commonly referred to as "The Tribe".
WNEW FM 102.7 in NYC was the First commercial station in the US to introduce a freeform format. It stayed that way under the ownership of Metromedia Broadcasting till it was sold and the new owners were not interested. WNEW FM was a leader in introducing new music and making household names of a good deal of the bands we know from the 1960's and 70's.