The Cleburne County Sheriff's Office said in a news release that McCready was found dead at a residence in Heber Springs from what appears to be a single, self-inflicted gunshot to the head. An autopsy is pending.
It wasn't the first suicide attempt for the troubled singer, whose list of problems only continued to grow in 2013.
McCready entered court-ordered rehab earlier this month after her father told a judge she was no longer taking care of herself or her children and was abusing drugs and alcohol. Her sons were put in foster care at the time, but it's not clear where Zander and Zayne were at the time of McCready's death.
McCready's longtime boyfriend David Wilson, the father of her younger son, died last month in Arkansas. Authorities found his body on the same porch where they discovered McCready's on Sunday, and his death also was investigated as a suicide.
The front porch light remained on Sunday night at McCready's home in the wooded lakefront community filled with large homes. Yellow crime-scene tape blocked off the front of the house, and a deputy sat watch over the property, referring questions to the sheriff. A pickup truck remained in the driveway.
Wilson's passing struck McCready hard. She issued a statement last month lamenting his death. She called him her soul mate and a caregiver to her sons in an interview with NBC's "Today." She said she'd never gone through anything as painful as his death.
"I just keep telling myself that the more suffering that I go through, the greater character I'll have," she said, according to a transcript of the interview.
News of McCready's death spread quickly Sunday night on Twitter, with major country stars paying their respects to the onetime Nashville darling.
"Too much tragedy to overcome. R.I.P Mindy McCready," wrote Natalie Maines of The Dixie Chicks.
And Jason Aldean added: "Just heard about Mindy McCready. My thoughts and prayers are with her 2 boys and her family."
Melinda Gayle McCready arrived in Nashville in 1994 still in her teens with tapes of her karaoke vocals and earned a recording contract with BNA Records.
In 1996, her "Guys Do It All the Time" hit No. 1 and its dig at male chauvinism endeared her to females. Her other hits included "Ten Thousand Angels," also in 1996, and her album by that title sold 2 million copies.
She spent the next 15 years chasing another hit as personal problems began plaguing her. Her problems included a custody battle with her mother over one of her sons, an overdose and discord in her love life.
McCready took her older son, Zander, from her mother and the boy's legal guardian, Gayle Inge, in late 2011. She fled to Arkansas without permission over what she called child abuse fears. Authorities eventually found McCready hiding in a residence without permission and took the boy into custody.
She and Wilson had a son, Zayne, in April 2012. The older son's father is McCready's former boyfriend Billy McKnight.
In May 2010, she was hospitalized briefly after police responded to an overdose call at a home in North Fort Myers, Fla., owned by her mother. This followed a stint on "Celebrity Rehab With Dr. Drew," where she declared herself to be clean from drugs. She is the fifth celebrity appearing on that show to have died.
But her troubles began earlier. In 2004, she was charged with obtaining the painkiller OxyContin fraudulently at a pharmacy. She pleaded guilty and was placed on three years' probation.
She violated the probation with a drunken driving arrest in May 2005. A few days after that arrest, she was beaten and her boyfriend at the time was charged with attempted criminal homicide. Then she attempted suicide in July 2005, overdosed in September 2005 and slit her wrists in December 2008.
Also that year, McCready was charged in Arizona with hindering prosecution and unlawful use of transportation. Those charges stemmed from an alleged attempt in June 2005 to purchase two high performance boats, but she claimed she was trying to stop a con man.
In July 2007, she was arrested in her hometown of Fort Myers, Fla., on misdemeanor charges of scratching her mother on the face during a scuffle and resisting sheriff's deputies.
She made headlines again in April 2008 when she claimed a longtime relationship with baseball great Roger Clemens. Published reports at the time said she met the pitcher at a Florida karaoke bar when she was 15 and he was 28 and married.
In June 2008, McCready was arrested and charged with violating her probation by falsifying her community service records relating to the 2004 drug charge. A month later, she entered an extended care facility for undisclosed treatment, and followed that with a 60-day jail sentence in the Williamson County jail.
McCready found some peace after her appearance on "Celebrity Rehab" and told The Associated Press in early 2010 she hoped to get her career restarted, write a book about her experiences and begin production on a reality show. She felt she'd finally gained some control over her life.
"It is a giant whirlwind of chaos all the time," she said. "I call my life a beautiful mess and organized chaos. It's just always been like that. My entire life things have been attracted to me and vice versa that turn into chaotic nightmares or I create the chaos myself. I think that's really the life of a celebrity, of a big, huge, giant personality."