M-type Strontium Hexaferrite (SrFe12O19) is prepared using citrate precursor sol-gel method. The X-ray spectrum confirms that synthesized nanomaterials were in a pure phase with the hexagonal crystal symmetry with P63/mmc space group. The Williamson-Hall plot is utilized for calculating crystallite size and lattice strain in hexaferrite nanomaterials. Lattice parameters (a) and (c) show noticeable increments due to induced lattice strains in samples. Raman spectra and FTIR spectrum well support the XRD results. The magnetic parameters of nanomaterials got refined with annealing, with appreciable Magnetization 26.91–71.74 emu/g and Retentivity 21.41–29.02 emu/g. Coercivity drastically increased from 316 to 6105 Gauss. Curie temperature got shifted to 472 °C from 450 °C. The higher Curie temperature will enable these hexaferrite preferences in high temperature magnetic devices. A correlation of induced lattice strain with structural and magnetic properties enrichment with varying annealing temperatures is explored in this article.