In this study, waste corrugated cardboard (WCC) was selected as a feedstock to prepare carboxymethyl cellulose. Compositions of untreated WCC were α-cellulose 63.09±0.985%, hemicellulose 10.85±0.924% and lignin 11.92±0.351%. Waste cardboard was hydrolyzed (hot water and 80% acetic acid-70% nitric acid) and delignified (2% concentration H2O2 (pH=12 with 12M NaOH)) to extract α-cellulose with total chlorine free (TCF) method. The yield of α-cellulose was 39.67±0.928% with 94.5±0.481% purity, which contained 2.08±0.184% hemicellulose and 1.03±0.067% lignin. Carboxymethyl cellulose was synthesized from purified α-cellulose by mercerization followed by etherification process, respectively in alcoholic medium. The effect of carboxymethylation factors such as, sodium monochloroacetate loading (2, 6 and 10 g), NaOH concentration (5, 25 and 45 %w/v) and temperature (30, 50 & 70 oC) were optimized using response surface methodology/central composite face centered. Based on CCFC optimization the value of degree of substitution and apparent viscosity of CMC were found to be 1.84 and 137.82 mPa.s, respectively, with 0.942 desirability function under optimum process parameters of 23.99% NaOH concentration, 3.62 g sodium monochloroacetate loading and 54.74 oC etherification temperature, under benzene-ethanol mixture as solvent medium. The physicochemical properties of optimized CMC (DS=1.83±0.01) were studied at the optimum condition. The moisture content of CMC was found to be 6.37±0.002% and 2% CMC solution had a pH of 7.31±0.129 at 25oC, yield of CMC was found to be 125.01±4.245% while purity was 85.74±1.85%. The swelling capacity was found to be 9.03±2.065 g/g whereas, moisture sorption was found to be 80.81±0.012%. The conformity of α-cellulose and CMC was determined by identifying the functional groups, crystallinity and thermal stability in comparison to commercial CMC using FT-IR, XRD spectroscopy and TGA instrument, respectively. The rheological properties of 2% w/v CMC solution with different shear rate was studied at optimized condition.