“Bernie’s Tune” was popularized by the Gerry Mulligan Quartet when their recording of it and “Lullaby of the Leaves” became a hit in 1952.

According to the liner notes of Mulligan’s Jeru LP, written by Joop Visser,

“Bernie’s Tune,” a minor key 32 bar AABA tune...was a popular tune for jamming with musicians at the time. Mulligan often stated that his aim was to simplify rather than complicate and this is certainly the case with his handling of “Bernie’s tune” with its tightly orchestrated unisons by trumpet, baritone sax and bass, Mulligan’s improvised background behind Chet [Baker]’s solo, the carefully arranged drum part that underpins the proceedings and the somewhat strained “baroque” passage before the final chorus...[Jazz record producer] Dick Bock released “Bernie’s Tune” and “Lullaby of the Leaves” as the first single on his newly founded Pacific Jazz label...The success of the record put Pacific Jazz in business and helped to give the Gerry Mulligan quartet its first big break.

This was truly a landmark recording. In the liner notes of Gerry Mulligan and His Sextet’s Mainstream of Jazz, Volume 2, Ira Gitler says,

A recording of “Bernie’s Tune” launched the Pacific Jazz label and, in effect, the West Coast jazz movement because of the attention it focused on the L.A. scene. West Coast jazz came to be known as a synonym for pallid, watered-down expression but Mulligan’s music has always transcended any categories in which people tried to trap it.

Although “Bernie’s Tune” is often associated with Gerry Mulligan, it was written by Bernie Miller who also composed “Loaded,” a jazz tune that has been covered by Chet Baker, Stan Getz, Vido Musso, Kai Winding, and Peter Griesar.

There is not much information generally available on Miller--he is usually described simply as a piano player from Washington D.C. Some accounts have Miller writing “Bernie’s Tune” specifically for Mulligan but Mulligan claims he never met him. In Gordon Jack’s book, Fifties Jazz Talk: An Oral Retrospective, Mulligan says,

Bernie Miller wrote “Bernie’s Tune,” but I never knew him. As far as I know, he was a piano player from Washington D.C., and I think he had died by the time I encountered any of his tunes. He had a melodic touch, and he wrote a couple of other pieces that musician’s liked to play.

“Bernie’s Tune” is sold by sheet music publishers with a copyright date of 1953, but as with many jazz tunes, it was written and recorded at an earlier time. The exact date is questionable but some recordings predate the copyright by at least three years. According to Thom Jurek, writer for All Music Guide, the Brew Moore retrospective CD titled The Kerouac Connection includes “Bernie’s Tune,” which was “recorded for Canadian television in 1950 with a young Paul Bley on piano.”

In 1952 Mulligan’s Quartet consisted of Mulligan (barsx), Chet Baker (tp), Bob Whitlock (b) and Chico Hamilton (d). Their recording of “Bernie’s Tune” took place at the Laurel Canyon bungalow of recording engineer Phil Turetsky using his Ampex tape recorder.

“Bernie’s Tune”also turned up on a couple of LPs in 1952 including Al Haig: Live In Hollywood (Xanadu 206), with Chet Baker (tp), Ted Ottison (tp), Sonny Criss (as), Jack Montrose (ts), Les Thomson (hca), Al Haig (p), Dave Bryant(b), and Larry Bunker(d).

In 1954 Gerry Mulligan filed a copyright for his arrangement of “Bernie’s Tune”and later had this to say about it (also from Fifties Jazz Talk: An Oral Retrospective):

The recording company wanted to put “Bernie’s Tune” in my name but I refused, because I always objected to bandleaders putting their names to something that wasn’t theirs, so I wasn’t going to do it to Bernie Miller whether I knew him or not. I told them to find out if he had a family so that the money could go to his heirs. If he didn’t have one, I would have claimed it to stop it going into the public domain.

And in 1955 songwriters Mike Stoller and Jerry Leiber, (“Hound Dog,” “Kansas City,” “Young Blood,” “Searchin’,” “Yakety Yak,” “There Goes My Baby,” “Jailhouse Rock”) penned lyrics to “Bernie’s Tune” purporting,

It’s so easy to whistle, It’s so easy to sing, Even hummingbirds hum it, It’s the thing.
...
Millionaires, Even squares, Whistle Bernie’s tune.
...

Regarding the lyrics Gerry Mulligan says (again, from Fifties Jazz Talk: An Oral Retrospective),

... Lieber and Stoller wrote a lyric for it, which I thought was a little presumptuous; I hated the damn thing. They were nice enough fellows, but I really resented them doing that.

In 1976 Mulligan wrote a new melody for “Bernie’s Tune,” keeping the same chord changes and titling it “Idol Gossip.” It became the title track of his album that year.