$\boldsymbol{\alpha_S}$ extraction and PDF constraints from jet measurements at CMS

We present recent CMS results related to the extraction of the strong coupling constant and constraints on parton distribution functions. Results are based on recent jet measurements performed with 2011 data taken at center-of-mass energy of 7 TeV. $\alpha_S$ extraction is based on measurements of multijet events and inclusive jet production cross sections, with the latest to be used also for setting constraints on the parton distribution functions.