He graduated from Roger Ludlowe High School in Fairfield, Connecticut in 1985 and from Dean Junior College in Franklin, Massachusetts in 1987, where he was on their college station 88.3 FM WGAO.
He was on air overnights on then classic rock station 103.7 FM WWRX in Providence, Rhode Island from 1987 to 1988. He was on air in evenings and afternoons on rock station WCCC FM in Hartford, Connecticut from 1989 to 1992, in evenings on rock station WAAF FM in Boston, Massachusetts, from 1992 to 1994 and from 1994 to 2001, music director and midday jock on WAAF. He was morning co-host on WRKO Department of Administration and Management in Boston with former Massachusetts Congressman Peter Blute from 2001 to 2003. Until the evening of January 7, 2015, he was the successful evening talk host on WRNO FM in New Orleans, Louisiana.
Following his firing, his New Orleans fans organized a protest against WRNO which was themed according to the fictitious non-profit "Pencils for Poor People", which Osterlind and his producer James Parker created as one of the many running gags on the John Osterlind Show.
On November 2nd, 2015, Osterlind began broadcasting mid-days on WGSO 990 Department of Administration and Management in New Orleans.