In 2004, McCready was placed on three years' probation after she pleaded guilty to fraudulently obtaining the painkiller OxyContin at a pharmacy.
The next year, she was arrested in Nashville for drunken driving, and was allegedly beaten and choked by ex-boyfriend Billy McKnight, who was charged with attempted murder.
"Yes, things have been going bad," she told CNN in 2005. "I think it's God's way of getting my attention, saying, 'You better wake up, girl. I have important stuff for you to do in life,' and I've definitely been preoccupied or sidetracked doing the wrong things."
Before 2005 ended, McCready had suffered two drug overdoses, was arrested on drug charges, was pregnant with McKnight's child and, authorities say, attempted suicide.
She attempted suicide again in 2008, authorities say, and overdosed again on drugs in 2010 before joining the cast of VH1's "Celebrity Rehab with Dr. Drew." The reality show chronicles the lives of celebrities as they're treated for alcohol and drug addiction.
Dr. Drew Pinsky said he contacted McCready last month after her boyfriend's death.
"When I heard she was struggling, I did reach out to her and urged her to go to take care of herself, get in a facility if she felt she needed," said Pinsky, who hosts a program on CNN's sister network HLN.
"Her biggest fear was the stigma of doing so and what people would think if she, God forbid, took care of herself. And this to me is the most distressing part of this story. She is a lovely woman, we have lost her, and it didn't have to go down like this."
On one episode of the show, McCready performed "I'm Still Here," dedicating it to the other cast members, who included Dennis Rodman, Heidi Fleiss and Mackenzie Phillips.
"When I was writing this song, I was in jail," the singer said tearfully. "I never knew it, but I was writing for all of you."
In recent years, McCready had waged a public battle for custody of her elder son, Zander, whose father is McKnight.
In 2011, she took the boy from her mother, who had legal custody, and fled with him to her home in Arkansas, saying she had concerns over his safety.
A judge ordered authorities to pick up the boy and, days later, authorities found the boy and McCready in a closet at her home.
In addition to her relationship with McKnight, McCready had romances with musician David Malloy and actor Dean Cain; she also said she had had an affair with baseball player Roger Clemens, which he didn't confirm or deny.
But Clemens did issue a statement Monday from training camp with the Houston Astros in Kissimmee, Florida. "Yes, this is sad news," he said. "I had heard over time that she was trying to get peace and direction in her life. The few times that I had met her and her manager/agent they were extremely nice."
In 2010, Vivid Entertainment released a porn video called "Mindy McCready, Baseball Mistress" that featured McCready having sex with a man referred to as "Peter" and talking about her exploits with Clemens.
Sunday night, country music stars offered their condolences as they learned of McCready's death.
"My heart goes out to Mindy McCready's family. I knew her well," singer LeAnn Rimes said on Twitter. "It's a horrible tragedy. May peace be with her sons."
Carrie Underwood said she grew up listening to McCready. And country artist Terri Clark said she had had some fun times with her "back in the day."
"I hope our society shows compassion and realizes the severity and reality of mental illness, and addiction," she tweeted.
Singer Wynonna Judd posted a series of tweets also calling attention to addiction and mental illness.
"It breaks my heart what addiction continues to take from this life," she said. "Addiction is a disEASE & not a character flaw. When the pain becomes too much, it causes people to want that pain to stop. This is just so unbelieveable & so sad."