Carrot (Daucus carota L.) having a family of Umbelliferea, is a winter crop and is used fresh or in processed form throughout the world. For early carrot production, problem of seed germination exists due to high temperature at the start of August in Punjab, Pakistan. To cope with the issue, a comprehensive research was performed at Institute of Horticultural Science, University of Agriculture, Faisalabad. The present study had focused to enhance high temperature tolerance in carrot seed that resulted in better germination by using pre-sowing seed treatments. For the purpose, Seeds of carrot cultivar T-29 were primed with various concentrations of different chemicals, i.e GA3, Kinetin, IAA, SA, KNO3 or with distilled water, and evaluated in laboratory (35±2 oC) in comparison with unprimed seeds (control)to optimize the best concentration (priming dose) from each chemical under high temperature stress (35±2 oC) in term of final germination percentage and other related traits. Pre-sowing seed treatments significantly improved almost all the parameters under study i.e., SA 0.1 mM followed by GA3 0.05 mM and KNO3 50 mM showed promising results for seed germination and seedling vigour related attributes. Two best performing doses from each chemical, which gave maximum germination under high temperature stress in Laboratory, were selected for field evaluation. Seed inoculation was also performed with azotobactor. Thereafter, primed, inoculated and unprimed seeds tested in the field under RCBD and treatment means were analyzed. All the pre-sowing seed treatments enhanced the final emergence percentage. Carrot root quality (colour, diameter, weight and length), sugars (reducing, non-reducing and total sugars, TSS) ascorbic acid contents, antioxidants enzyme activities, malondialdehyde contents, total phenolic, total antioxidants, photosynthetic rate, transpiration rate, stomatal conductance and water use efficiency of plants were positively improved by pre-sowing seed treatments, SA 0.1 mM performed the best followed by GA3 0.05 mM. In the field condition, maximum emergence (33.2%) was achieved with GA3 0.05 mM followed by SA 0.1 mM 30.5%, priming treatments in comparison with control (14.8%), while carrot root yield was enhanced upto (2.82 kg/12.5 ft2 against 0.1 mM SA priming treatment) as compared to unprimed seeds (1.72 kg/12.5 ft2). It was revealed that carrot seed priming with SA 0.1 mM solution and/ or GA3 0.05 mM solution could be a good strategy for enhancing emergence with healthy seedlings and establishment as well as further growth and production of early carrot crop at high temperature.