Morgan was born in Nashville, Tennessee, and made her first appearance on the Grand Ole Opry at age 13, performing Fred Spielman and Janice Torre's "Paper Roses". After her father died in 1975, she took over his band at age 16 and began leading the group through various club gigs. After disbanding the group, she joined the Little Roy Wiggins band in 1977. She then became a receptionist and demo singer at Acuff-Rose Music, where she also wrote songs. In the late 1970s, she was the featured vocalist on a morning television show hosted by Ralph Emery, on Nashville's WSM-TV (now WSMV); Emery was a longtime friend of her father, who appeared on Emery's Opry Star Spotlight, an overnight music and interview show that ran for many years on WSM-AM.

Morgan had one minor hit single in 1978; the following year she recorded another minor hit with "I'm Completely Satisfied With You," an electronically dubbed duet with her father who died in 1975. She began touring Nashville nightclubs and opened for a number of acts, including Jack Greene, Billy Thunderkloud and Jeannie Seely. She toured as a duet partner with George Jones and spent two years as part of the Opryland USA bluegrass show and as a regular singer on TNN's Nashville Now.

She has a daughter, Morgan Anastasia Gaddis (born December 22, 1980) from her first marriage to Ron Gaddis, a former bass player in George Jones' band; they were married for only a brief time from 1979 to 1980. She has a son, Jesse Keith Whitley (born June 15, 1987) with her second husband, Keith Whitley. That marriage lasted from 1986 until his death in 1989. After that marriage, she had a lengthy involvement with Dallas Cowboys quarterback Troy Aikman. In 1991, she married Brad Thompson, the one-time bus driver for Clint Black; they divorced in 1993.

In 1984, Morgan scored a minor hit with "Don't Go Changing." That year she became the youngest singer ever to join the Grand Ole Opry. Four years later, she signed with RCA Records, her first major label; her first album on that label, Leave the Light On, was released in 1989.

In 1990, Morgan had her first number one single, "Five Minutes." Morgan's second album, Something in Red, was released in 1991 and went platinum. The same year, she married her third husband, Brad Thompson, Clint Black's bus driver. Watch Me, her third album, was released on RCA's newest label, BNA Records; it contained the number-one single, "What Part of No." Watch Me also was certified platinum, making Morgan the first female country Artist to have three albums in a row to be certified platinum. Morgan's romantic life gained tabloid attention with Dallas Cowboys quarterback Troy Aikman.

From 1994 to 1996, Morgan was romantically linked to actor and Politician Fred Thompson. In her autobiography Forever Yours, Faithfully: My Love Story, Morgan describes their relationship:

Morgan's Greatest Hits album, which produced her third and, to date, last number-one single in the song "I Didn't Know My Own Strength", was released in 1995. The next year, Morgan was featured on the Beach Boys' now out-of-print album, Stars and Stripes Vol. 1, performing a cover of their 1964 hit, "Don't Worry Baby." The Beach Boys provided the harmonies and backing vocals. Lorrie appeared on the 2006 album She Was Country When Country Wasn't Cool: A Tribute to Barbara Mandrell.

In 1996 Morgan married singer-songwriter Jon Randall. She married her fifth husband, singer Sammy Kershaw, on September 29, 2001. Morgan filed for divorce, citing irreconcilable differences on October 23, 2007. On September 15, 2010, Morgan married Tennessee businessman Randy White in a beachside ceremony.

Morgan is also known for her turbulent personal life, having been married six times. In a July 2004 appearance on Larry King Live, she told Larry King that "drama is something that lets you know you're still alive."

In October 2008, Morgan filed for Chapter 7 bankruptcy, citing up to $10 million in liabilities while listing her own assets as valued between $500,000 and $1 million.

Morgan's eleventh album A Moment in Time was released on October 27, 2009, on the Stroudavarious label. It features fourteen covers of traditional country songs. In December 2010, Morgan released her twelfth studio album I Walk Alone on iTunes and Amazon download. This was followed in 2014 by Dos Divas, a collaboration album with Pam Tillis. Morgan released a further solo album in 2016, Letting Go...Slow and a second duets album with Tillis in 2017, Come See Me and Come Lonely.