This contribution reports the molecular-level conformations of the backbone and side chains of thermosensitive bottlebrush polymers (BBPs) of poly(N-isopropylacrylamide) (PNIPAM) in water. Here, for the first time, realistic coarse-grained (CG) models of PNIPAM and explicit water that can accurately capture its lower critical solution temperature (LCST) were employed. The effect of PNIPAM grafting density, side-chain length, and hydrophobic backbone length was studied by performing simulations at 290 and 320 K. These are below and above the LCST of PNIPAM, respectively. BBPs with 12 (grafting density, similar to 16%), 24 (similar to 33%), 36 (similar to 50%), and 72 (similar to 100%) chains of 30, 18, 10, and 5 monomers of PNIPAM on the backbone with 72 beads were generated. For BBPs with 30-mer and 18-mer PNIPAM chains, they show that they are in a coil-like and a globule-like state below and above their LCST, respectively, up to 50% grafting density. At 100% grafting density, majority of PNIPAM chains are collapsed both below and above LCST due to their dehydration. For BBPs with 5-mer and 10-mer of PNIPAM, they behave like an elastic rod both below and above LCST. The backbone attains coiled-coil conformation with an increase in the grafting density in all the systems. The metric multidimensional scaling (MDS) method was utilized to analyze conformations of the backbone of the BBPs, and it shows that the backbone of BBPs with lower grafting densities exhibits more numbers of metastable states and explores more conformational spaces as compared to higher grafting densities. MDS analysis also shows that BBPs with 5-mer side chains for lower grafting density exhibit more metastable states as compared to those with 30-mer side chains. The BBPs with 9, 36, and 72 bead backbones suggest that, with a decrease in the backbone length, even at 100% grafting density, PNIPAM chains exhibit a coil-like and a globule-like state at 290 and 320 K, respectively. The MDS analysis shows that, with an increase in the backbone length, the number of metastable states increases. The knowledge gained from this study can be useful for experimental scientists in controlling the conformations of the backbone and individual side chains of thermosensitive BBPs, which are responsible for their properties and function.