The 22-year-old, who is battling pneumonia, received the award for her role in David O Russell's 'Silver Linings Playbook'.
"Everyone is scared of me, I'm like, 'I'm fine'. I had walking pneumonia and it is highly contagious," contactmusic.com quoted Lawrence as saying.
Tommy Lee Jones won the award for the best supporting actor in a motion picture for 'Lincoln', while Anne Hathaway bagged the best supporting actress trophy for her role as Fantine in 'Les Miserables'.
Here is the complete list of winners for 2013 SAG Awards.
Supporting Actor, Motion Picture: Tommy Lee Jones ('Lincoln')
Supporting Actress, Motion Picture: Anne Hathaway ('Les Miserables')
Action Performance by a Stunt Ensemble, Film: 'Skyfall'
Action Performance by a Stunt Ensemble, Television Series: 'Game of Thrones'
Lifetime Achievement: Dick Van Dyke
Actor, Television Series, Comedy: Alec Baldwin, ('30 Rock')
Actress, Television Series, Comedy: Tina Fey, ('30 Rock')
Ensemble Cast, Television, Comedy: 'Modern Family'
Actress, TV Movie or Miniseries: Julianne Moore, ('Game Change')
Actor, TV Movie or Miniseries: Kevin Costner, ('Hatfields & McCoys')
Actor, Television Series, Drama: Bryan Cranston, ('Breaking Bad')
Actress, Television Series, Drama: Claire Danes, ('Homeland')
Outstanding Ensemble Cast, Television Series, Drama: 'Downton Abbey'
Actress, Motion Picture: Jennifer Lawrence ('Silver Linings Playbook')
Actor, Motion Picture: Daniel Day-Lewis ('Lincoln')
Ensemble Cast, Motion Picture: 'Argo'