Howard's biggest hit and signature song was the 1966 country hit "Evil on Your Mind", which peaked at number five on the Billboard country charts. The song is included in the book Heartaches By the Number: The 500 Greatest Country Music Singles. In the late 1960s and early 1970s, she dueted with Bill Anderson on a number of top-10 hits, including the number-one hit "For Loving You".
Howard was born in West Plains, Missouri, in 1930, one of eight children. At age 15, she married, and soon had children. After dealing with two unsuccessful marriages, she moved to Los Angeles, California, where she met aspiring songwriter Harlan Howard. They married in Las Vegas one month later. One evening, she was singing while washing dishes in her kitchen and Harlan heard her sing for the first time, and liked what he heard. He thought Jan had talent and wanted her to become a country music singer.
Harlan persuaded Jan to make a demonstration (demo) tape of one of the songs he wrote, "Mommy For a Day". The song was later a big hit for Kitty Wells. She soon worked as a demo singer for her husband, singing demos for other country artists, such as Buck Owens and Tex Ritter. Jan Howard originally sang the demo for the Patsy Cline hit "I Fall to Pieces".
In 1959, she made her debut as a recording artist backed by Wynn Stewart's band. She recorded her first song that year called "Yankee Go Home", along with the Harlan Howard composition, "Pick Me Up on Your Way Down" (which was once recorded by Charlie Walker).
In 1959, under the name Jan Howard, she released the single "Yankee Go Home", which failed to hit the country charts. In 1960, the Howards went to Nashville, Tennessee, where they appeared on The Prince Albert Show, the Grand Ole Opry segment carried nationally by NBC Radio. Howard then released her first single under her new record company, Challenge. Titled "The One You Slip Around With", the song was Howard's first significant country hit, hitting the top 15, peaking at number 13 on the Billboard country music chart and earning her several Most Promising Female Vocalist awards (over, among others, another newcomer, Loretta Lynn). Occasional appearances on the Grand Ole Opry led to friendships with several country singers, including Patsy Cline. According to Cline's 1980 biography, Honky Tonk Angel, Cline originally yelled at Howard after a performance on the Opry stage. Howard fought back, and Cline was shocked by her reply. Cline then said to Howard, "Anybody who stands up to Cline is all right, we're gonna be good friends." The two were good friends until Cline's death in 1963.
Meanwhile, painfully shy Jan was suffering from the psychological scars of her youth, as well as the anxiety of beginning a new adventure. When her weight dropped below 97 pounds, Harlan hospitalized Jan and she went into therapy.
Howard appeared on ABC-TV's Jubilee USA on February 6, 1960, and later that year she won Billboard magazine's Most Promising Female Country Award. In 1962, she charted successfully on the country charts at number 27 with, "I Wish I Was a Single Girl Again". However, none of Howard's follow-up singles was successful.
Jan Howard signed with Decca Records in 1965 and immediately had a career upswing. Her first Decca record, "What Makes a Man Wander", hit the top 25 on the country charts; 1966's "Evil on Your Mind" was the biggest solo hit of Howard's career, hitting number five on the Billboard chart. The follow-up to "Evil on Your Mind" was "Bad Seed". The song reached the top 10 in 1966. Howard began recording duets with singer Bill Anderson and joined his syndicated television show and touring act as his "girl singer". Their first duet record was a remake of "I Know You're Married (But I Love You Still)". The duo went on to have several top 10 songs, including the 1967 number one hit, "For Loving You".
Between 1967 and 1972, Howard chalked up a number of solo of top 40 hits, such as "Roll Over and Play Dead" (1967), "Any Old Way You Do" (1967), and "I Still Believe in Love" (1968). Top 20 hits from this time include "My Son" (1969) and "We Had All the Good Things Going" (1969). "My Son", a recitation song, was Howard's most personal composition. She dreamed in 1968 that her son, who was fighting in the Vietnam War, would be killed in battle, which came true. Her son died that year. The song was a top 15 country hit in 1969. Howard was also an accomplished songwriter. In 1966, she wrote the Kitty Wells hit "It's All Over But the Crying", and in 1970 she wrote the Bill Anderson hit "Love Is a Sometimes Thing". Together, Bill and Jan wrote the 1970 Connie Smith hit "I Never Once Stopped Loving You". She co-wrote "Dis-Satisfied" with one of her three sons, Carter Howard.
In 1970, Howard and Anderson's record "If It's All the Same to You" hit number two on the country charts that year, just missing the top spot. Their album of the same name was released that year also. Their 1970 album Bill and Jan or Jan and Bill spawned two more top-10 country singles, "Someday We'll Be Together" (1970) and "Dis-Satisfied" (1971). In 1970 and 1971, the duet pair was nominated for Vocal Duo of the Year by the CMA Awards. Howard's solo recordings began to be somewhat less successful in the early 1970s, hitting the top 40 as a soloist only twice with "Rock Me Back to Little Rock" (1970) and "Love is Like a Spinning Wheel" (1972).
Howard's son David committed suicide. This devastated Howard, still reeling from her older son's death in Vietnam four years earlier, and she seriously considered quitting the music industry. She did limit her personal appearances for many years, retiring from the Bill Anderson touring show and ultimately replaced by Mary Lou Turner. In 1973, she left Decca Records (shortly after it changed into MCA Records) and recorded for several smaller labels, hitting the back of the country charts several times into the late 1970s. In 1976, she began appearing with Johnny Cash's touring show, performing as a soloist and as a backup member of the Carter Family, until being fired by Cash in 1980. References made by the media regarding an affair between Howard and Cash were rather poorly dismissed by Cash, and Cash biographies leave the question unresolved.
In 1978, Howard began occasionally performing as a background vocalist for her friend Tammy Wynette. She still performed as a soloist on the Grand Ole Opry and in concert, however.
Since March 27, 1971, Howard has been a member of the Grand Ole Opry. She has toured every state in the United States, and has also toured in 21 countries. She has also appeared on The Today Show, Family Feud, and Hee Haw. In 1984, Howard released the album Tainted Love, and that same year she published her autobiography, Sunshine and Shadow.
In 1990, Howard remarried. In 2005, she was inducted into the Missouri Country Music Hall of Fame. Most recently, she has released a box set called Through the Years. Her hometown of West Plains, Missouri, pays homage to Howard by observing a Jan Howard Day annually. In West Plains, the US 63 bypass is known as the Jan Howard Expressway. In 2002, Howard made her acting debut with a small role in the feature film Changing Hearts starring Faye Dunaway, which featured Howard's friend, country singer Jeannie Seely.
In 2017, Howard, alongside Jessi Colter, appeared on Jeannie Seely's album Written In Song, singing on the track "We're Still Hangin' In There Ain't We Jessi". This is Howard's first musical release since a 2012 compilation album.