Fender dropped out of high school at age 16 in 1953, and when he turned 17, he enlisted for three years in the U.S. Marine Corps. He served time in the brig on several occasions because of his drinking, and he was court martialed in August 1956 and discharged with rank of private (E-1). According to Fender, he later received a letter from the U.S. Department of the Navy saying that he had been wrongfully discharged dishonorably because of alcoholism, and he was given a general discharge. He returned to Texas and played nightclubs, bars, and honky-tonks throughout the south, mostly to Latino audiences. In 1957, then known as El Bebop Kid, he released two songs to moderate success in Mexico and South America: Spanish-language versions of Elvis Presley’s “Don’t Be Cruel” (as “No Seas Cruel”) and Harry Belafonte’s “Jamaica Farewell.” He also recorded his own Spanish version of Hank Williams’s “Cold Cold Heart” under the title “Tu Frío Corazón” (“Your Cold Heart”).

He became known for his rockabilly music and his cool persona as Eddie con los Shades. In 1958 he legally changed his name from Baldemar Huerta to Freddy Fender. He took the name Fender from the guitar and amplifier, and Freddy because the alliteration sounded good and would “sell better with Gringos!” He then relocated to California.

In 1959 Fender recorded the blues ballad “Wasted Days and Wasted Nights.” The song was a hit, but he was beset by legal troubles in May 1960 after he and a band member were arrested for possession of marijuana in Baton Rouge, Louisiana. After serving nearly three years in the Louisiana State Penitentiary, he was released through the intervention of then-governor Jimmie Davis, also a songwriter and musician. Davis requested that Fender stay away from music while on probation as a condition of his release. However, in a 1990 NPR interview on Fresh Air with Terry Gross (rebroadcast October 17, 2006), Fender said that the condition for parole was to stay away from places that served alcohol.

In 1974 Fender recorded “Before the Next Teardrop Falls.” The single was selected for national distribution and became a number-one hit on the Billboard Country and Pop charts. It sold over a million copies and was awarded a gold disc by the RIAA in May 1975. His next three singles, “Secret Love,” “You’ll Lose a Good Thing,” and a remake of “Wasted Days and Wasted Nights,” all reached number one on the Billboard Country charts. Between 1975 and 1983 Fender charted 21 country hits, including “Since I Met You Baby,” “Vaya con Dios,” “Livin’ It Down,” and “The Rains Came.” “Wasted Days and Wasted Nights” became Fender’s second million-selling single, with the gold disc presentation taking place in September 1975.

Fender also was successful on the pop charts. Besides “Before the Next Teardrop Falls” reaching number one on the pop charts in May 1975, “Wasted Days And Wasted Nights” went into the pop top 10 and “Secret Love” into the top 20. “Since I Met You Baby,” “You’ll Lose A Good Thing” (his last pop top 40), “Vaya con Dios,” and “Livin’ It Down” (his last to reach the pop top 100) all did well on the pop charts.

Fender was heavily influenced by the swamp pop sound from southern Louisiana and southeast Texas as is shown by his recording swamp pop standards on his 1978 album Swamp Gold. One of his major hits, “Wasted Days and Wasted Nights,” has a typical swamp pop ballad arrangement. Fender associated with swamp pop musicians such as Joe Barry and Rod Bernard and issued many recordings on labels owned by Huey Meaux, a Cajun who specialized in swamp pop. As music writer John Broven observed, “Although Freddy was a Chicano from Texas marketed as a country artist, much of his formative career was spent in South Louisiana; spiritually, Fender’s music was from the Louisiana swamps.”

In 1988 Fender played the mayor of a small town in the Robert Redford–directed film The Milagro Beanfield War. Fender also appeared as Tony in the prison movie Short Eyes, a 1977 film adaptation, directed by Robert M. Young, of the Miguel Pinero play. Fender played the role of Pancho Villa in 1979’s She Came to the Valley (later released as Texas in Flames). The movie was directed by Albert Band and based on the book by Cleo Dawson. Fender also appeared as himself in an episode of the television series The Dukes of Hazzard.

In 1989 Fender teamed up with fellow Tex–Mex musicians Doug Sahm, Flaco Jiménez, and Augie Meyers to form the Texas Tornados, whose work meshed conjunto, Tejano, R&B, country, and blues to wide acclaim. When the Texas Tornados went to audition for Warner Bros. Records, Fender did not think that the group was strong enough, so he brought his own band. The audition was nearly a bust, because he played country music and that was not what the executives were looking for. Fender was persuaded to play some vintage rock and blues numbers, which was what the executives were looking for, and was subsequently given a record contract. After being a solo act, Fender was not sure if signing with a group was a good thing, but according to Fender, he “just wanted to record for a major label.” The group released four albums and won a Grammy in 1990 for Best Mexican American Performance for the track “Soy de San Luis”. Fender described the group in this way: “You’ve heard of New Kids on the Block? Well, we’re the Old Guys in the Street.” Following the death of Sahm, the Tornados’ production slowed. A live 1990 appearance on TV’s Austin City Limits, one of three the group made, was released in 2005 as part of the Live From Austin, Texas, series.

In 2001 Fender made his final studio recording, a collection of classic Mexican boleros titled La Música de Baldemar Huerta that brought him a third Grammy award, this time in the category of Latin Pop Album. Rose Reyes, who worked with Fender in 2004 for a Texas Folklife and Austin tribute titled “Fifty Years of Freddy Fender,” said of the album: “When he did Mexican standards at that point in his career, I expected it to be good because he’s a perfectionist. But that record is so beautifully recorded; his voice is perfection. I was so proud it was coming back to his roots.”

On March 13, 2001, Fender was erroneously reported to be dead by Billboard. He laughed off the magazine’s error. He underwent a kidney transplant in 2002 with a kidney donated by his daughter and underwent a liver transplant in 2004. Nonetheless, his condition continued to worsen. He was suffering from an “incurable cancer” in which he had tumors on his lungs. On December 31, 2005, Fender performed his last concert and resumed chemotherapy.

He had said in a 2004 interview with the Associated Press that he wished to become the first Mexican American inducted into the Country Music Hall of Fame.

He died on October 14, 2006, at the age of 69 of lung cancer at his home in Corpus Christi, Texas, with his family at his bedside. He was buried in his hometown of San Benito.

On June 25, 2019, The New York Times Magazine listed Freddy Fender among hundreds of artists whose material was reportedly destroyed in the 2008 Universal fire.