Kashara was admitted to Niigata University of Health and Welfare without consideration for his baseball talent and was able to, over time, increase his velocity from throwing in the mid 130s (km/h) to throwing in the high 140s (km/h).In the 2016 university fall league, he achieved a 0.72 ERA, claimed the most wins title and was chosen in the Best 9.

[1] Kasahara was the 4th pick for the Chunichi Dragons at the 2016 Nippon Professional Baseball draft.

[1][2] On 9 December 2022, Kasahara was traded for Seiya Hosokawa in the 2022 Current Player Draft.

[3] He made only 2 starts for Yokohama in 2023, posting an 0–2 record and 4.50 ERA with 5 strikeouts in 6.0 innings of work.

On November 26, 2023, Kasahara signed with the TSG Hawks of the Chinese Professional Baseball League.