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Aimed at the problem that conventional approaches for mechanical property determination all need destructive sampling, which may be improper for in-service structures, the authors proposed a method to determine the quasi-static fracture toughness and impact absorbed energy from spherical indentation tests (SITs) in this study. The stress status and damage mechanism of SIT, Mode I fracture, Charpy impact tests, and related tests were first investigated through finite element (FE) calculations and scanning electron microscope (SEM) observations, respectively. It was found that the damage mechanism of SITs is different from Mode I fracture, while the Mode I fracture and Charpy impact test share the same damage mechanism. Taking the difference between SIT and Mode I fracture into consideration, the uniaxial tension and pure shear were introduced to correlate SIT with Mode I fracture. Based on which, the widely used critical indentation energy (CIE) model in fracture toughness determination from SITs was modified. The quasi-static fracture toughness determined from the modified CIE model was used in evaluating the impact absorbed energy by means of the dynamic fracture toughness and energy to crack initiation. Effectiveness of the new proposed method was verified through experiments on four kinds of steels, i.e. Q345R, SA508-3, 18MnMoNbR, and S30408.