She began her career at age twelve as a print model. During her early teen years she appeared in television commercials and was frequently seen in national print advertisements.
At the age of fifteen, Loughlin was cast in the ABC soap opera The Edge of Night, playing the part of Jody Travis, an aspiring dancer, appearing in the series from 1980 to 1983. From 1983 to 1988, Loughlin appeared a number of feature films and television guest spots. From 1988 to 1995, she was cast in her most notable role to date, as Rebecca Donaldson, Danny Tanner (Bob Saget)'s co-host and later Jesse Katsopolis (John Stamos') wife in the ABC sitcom Full House. Recurring during the second season, she became a regular for the remainder of the series run.
Within months after Full House ended, Loughlin co-starred with Tony Danza in the ABC sitcom Hudson Street (1995–1996), the series was canceled after one season.
In 1997, she starred alongside Bruce Campbell in the film In the Line of Duty: Blaze of Glory. In 2000, Loughlin co-starred opposite Treat Williams in the Fred Olen Ray-helmed thriller Critical Mass.
She also guest starred in Suddenly Susan, Spin City, Seinfeld and The Drew Carey Show and the superhero Black Canary in the short lived Birds of Prey series in 2002.
From 2004 to 2005, Loughlin co-created, produced and starred in the WB drama series Summerland. She played Ava, the aunt who raises three children after their parents die in a car accident. The series was canceled after two season due to low ratings on July 11, 2005. In 2007, Loughlin co-starred in the ABC sitcom In Case of Emergency with David Arquette. She appeared in the film Moondance Alexander (2007), co-starring with her former Summerland cast mate Kay Panabaker.
Loughlin was in attendance at Comedy Central's The Roast of Bob Saget which was hosted by John Stamos and premiered on August 17, 2008. At her table were Full House co-stars Dave Coulier and Jodie Sweetin.
In 2010, Loughlin starred in the television film Meet My Mom, which premiered on the Hallmark Channel on Mother's Day.
- Shenae Grimes and Tristan Wilds think of her as a Mother figure. When Loughlin left the show, she frequently sent them emails and Christmas cards and they still call her "Mom".
- Her character's name was originally supposed to be named Celia Mills.
- She almost didn't get the part as the producers should she was "Too established", but they reconsidered when realizing she completely understood her character's role.
- Admitted that Rob Estes constantly made her laugh, and any scene that showed them laughing was them genuinely having fun.
- In one episode, Debbie was supposed to be stoned. Lori had no idea what it was like to be stoned and had to research and ask others for tips. They all said the same thing; Laugh.