The troubled actress - who has endured a string of legal problems and stints in rehab in recent years - had her probation for a 2007 driving under the influence (DUI) conviction come to an end last week and she admits it has taken her some time to figure out that she needed to correctly address her difficulties in order to move forward.
She said: "It's a tremendous weight I feel has been lifted off my shoulders and I feel really grateful and just happy and ready to move forward. It's been several years and I did what I had to do, it's taken time to realize that but it's a good day."
Asked what made her change her attitude to the sentence, she said: "I think growing up and sitting back and seeing I had worked so hard to be something I wanted to be, which is in this industry, and sitting back and seeing I had let it fall apart, so looking at that and saying, 'OK this is not what I signed up for, wake up.' "
Lindsay also praised Judge Stephanie Sautner for the way she presided over her case - arranging regular hearings with deadlines of how much of her community service she had to complete each time - because the "structure" she was given finally made her adhere to her sentence.
She told website TMZ: "I think also Judge Sautner understood I'm good with the structure, being on set and that sort of thing, it made sense and worked right. It really did make a difference and I thank Judge Sautner for that actually."
Now her sentence is complete, the 'Mean Girls' star is hopeful she can put her career first and stop the spotlight being on her personal life.
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She said: "I think I became more of a celebrity and I'd like to bring the focus back to what it is I love to do and what I started in this business for, which is acting.
"I think this being in my past [now] means it is something I can achieve."
Earlier this month, Lindsay was accused of a hit-and-run by club manager Thaer Kamal, who says she knocked into him with her Porsche, but the actress insists the claims are totally "fabricated".
Addressing claims she is a party girl, she said: "I think it's funny people say I go clubbing. if I go to dinner, that's not a club, it's a restaurant.
"The one time I tried to go anywhere was a very close friend's birthday and someone fabricated a story that I grazed them with a car when I wasn't even driving."