“My Heroes Have Always Been Cowboys” is the title of a Sharon Rice/Sharon Vaughn-written song that appeared on the 1976 album Wanted! The Outlaws by Waylon Jennings, Willie Nelson, Jessi Colter, and Tompall Glaser. Willie Nelson performed the song in the 1980 movie The Electic Horseman and the song was used for the title of a 1991 film.
 
The Dallas Cowboys football team has used the phrase “My Heroes Have Always Been Cowboys” to associate the cowboy heroes with Dallas Cowboys players.
 
 
Wikipedia: Wanted! The Outlaws
Wanted! The Outlaws is an album by Waylon Jennings, Willie Nelson, Jessi Colter and Tompall Glaser, released in RCA Victor in 1976 and consisting of previously released material. Released to capitalize on the new outlaw country movement, Wanted! The Outlaws earned its place in music history by becoming the first country album to sell a million copies. The original liner notes were written by Chet Flippo, a contributor to Rolling Stone, and offer a short introduction and some praise on each artist involved with the project. The album quickly reached #1 on the country charts and peaked at #10 on the pop charts, with two hit singles, “Suspicious Minds” and “Good Hearted Woman”, released; the two peaked at #2 and #1, respectively, both featuring Jennings. Wanted! The Outlaws was reissued on CD on RCA Records in 1996 with ten bonus tracks; only one of these, Steve Earle’s “Nowhere Road”, had previously been unreleased.
 
Track listing
“My Heroes Have Always Been Cowboys” (Sharon Rice) – 2:48
Performed by Jennings  
 
OCLC WorldCat record
Wanted : the Outlaws : Waylon Jennings, Willie Nelson, Jessi Colter, Tompall Glaser.
by Outlaws (Musical group); 
Type:  Musical Score; English
Publisher: Hialeah, Fla. : Columbia Pictures Publications, ©1976.
OCLC: 3389656
Related Subjects: Country music. 
Document Type: Musical Score
Notes: Songs performed by The Outlaws; for voice and piano, with guitar chord diagrams. Lyrics also printed separately as text.
Description: 55 p. : ports. ; 30 cm.
Contents: My heroes have always been cowboys.-Honky tonk heroes (like me) .-I’m looking for blue eyes.-You mean to say.-Heaven or hell.-Suspicious minds.-Good hearted woman.-Me and Paul.-Yesterday’s wine.-“T” for Texas (blue yodel #1).-Put another log on the fire. 
   
Lyrics Playground
MY HEROES HAVE ALWAYS BEEN COWBOYS
(Sharon Rice / Sharon Vaughn)
Recorded by : Waylon Jennings; Willie Nelson.
 
I grew up a dreaming of being a cowboy
And loving the cowboy ways
 
Pursuing the life of my high-riding heroes
I burned up my childhood days.
I learned all the rules of the modern day drifter
Dontcha hold on to nothing too long.
Just take what you need from the ladies and leave them
With the words of a sad country song.
 
CHORUS
My heroes have always been cowboys
They still are it seems.
Sadly in search of and one step in back of
Themselves and their slow-moging dreams. (...)
 
Penn State Daily Collegian (April 2, 1976)
Waylon Jennings sings “My Heroes Have Always Been Cowboys” and “Honky Tonk Heroes.” They are thesort of hard-drinking and hard times songs he’s been doing for years. 
 
Wikipedia: The Electric Horseman
The Electric Horseman is a 1979 adventure and romance film starring Robert Redford and Jane Fonda and directed by Sydney Pollack. It was the third time Redford and Fonda had starred together in a film, having previously teamed on The Chase (1966) and Barefoot in the Park (1967).
(...)
Willie Nelson contributed significantly to the film’s soundtrack, singing five songs including “My Heroes Have Always Been Cowboys,” “Midnight Rider,” “Mamas Don’t Let Your Babies Grow Up to Be Cowboys,” “So You Think You’re a Cowboy” and “Hands on the Wheel.”
 
Internet Movie Database
My Heroes Have Always Been Cowboys (1991)