A native of Duncan, Oklahoma, Mooney became a key figure in the country music scene around Bakersfield, California.

He played on many records associated with the Bakersfield sound, including Wynn Stewart's "Wishful Thinking", Buck Owens' "Under Your Spell Again" and Merle Haggard's "Swinging Doors".

Though best known for his instrumental work, Mooney co-wrote "Crazy Arms" with Chuck Seals; the song was Ray Price's first No.

[7] At the age of 12, he moved to California to live with his sister and her husband; that brother-in-law would begin teaching Mooney to play guitar, fiddle, and mandolin.

[8] Stewart cut two singles, "I've Waited a Lifetime" (with Mooney playing lead guitar instead of pedal steel) and "Strolling".

[11] Ralph sold the song to Claude Caviness, who formed Pep Records in hopes of finding a hit for his singing wife Marilyn Kaye.

Caviness and Kaye, backed by Kenny Brown and the Arkansas Ramblers, cut a duet version of "Crazy Arms" in 1955.

Owens' next three singles, "Under Your Spell Again", "Above and Beyond," and "Excuse Me (I Think I've Got a Heartache)", each featuring Mooney's pedal steel kicking off the song and prominently throughout, reached numbers 4, 3, and 2, respectively.

Mooney asked Haggard if he could sing, Merle said "Sure", and the band ran through a few Marty Robbins songs, ending with "Devil Woman."

Mooney would play on Haggard's first four albums, all of which were top 10 country hits, with Swinging Doors and the Bottle Let Me Down and Branded Man/I Threw Away the Rose both reaching #1.

In 1967, the band was caught in a snow storm in Minneapolis; Mooney, tired of the hotel, tried to steal the Strangers' tour bus and drive it home himself.

[8][18] Mooney spent the last years of the 1960s doing sessions work, recording an instrumental album with James Burton, and sporadically playing with Wynn Stewart.

One such session at the Golden Nugget was overheard by drummer Richie Albright, who introduced Mooney to his boss, Waylon Jennings.

He did occasional session work as well, playing on Neil Young's Old Ways, Marty Stuart's Hillbilly Rock and two of the last albums Buck Owens recorded, Hot Dog!

[8] That same year he was inducted into the Steel Guitar Hall of Fame, In 1985, Wynn Stewart died of a heart attack at the age of 51.

Mooney played steel on the album, co-wrote a song with Stuart, and delivered an instrumental version of his own "Crazy Arms."

According to Bobbe Seymour, this began as a Magnatone double eight-string nonpedal steel guitar,[26] which Mooney modified with household materials.

[8] He was quoted as saying that the pedals were held in place with chicken wire strung between the legs; according to steel player Mike Neer, Mooney took this instrument to a session for Wanda Jackson, who saw him setting it up and said to her producer, "You better go get me someone who could play.

[31] In the 1970s, after joining Waylon Jennings' band, Mooney was gifted a double-neck Sho-Bud, which maintained the setup and tuning he had developed, including custom-wound pickups designed to emulate the sound of his Fender.

[33] At some point after this, Mooney began using instruments made by GFI, a company founded by Gene Fields, who worked as a designer at Fender during the development of their pedal steel line.

[34] With Wynn Stewart With Buck Owens With Merle Haggard With Waylon Jennings With Jessi Colter With Marty Stuart