In this work we have demonstrated the operation of 600-V class 4H-SiC vertical-channel junction field-effect transistors (VJFETs) with 6.6-ns rise time, 7.6-ns fall time, 4.8-ns turn-on and 5.4-ns turn-off delay time at 2.5 A drain current (IDS), which corresponds to a maximum switching frequency of 41 MHz – the fastest ever reported switching of SiC JFETs to our knowledge. At IDS of 12 A, a 19.1 MHz maximum switching frequency has been also achieved. Specific on-resistance (Rsp-on) in the linear region is 2.5 m·cm2 at VGS of 3 V. The drain current density is greater than 1410 A/cm2 at 9 V drain voltage. High-temperature operation of the 4H-SiC VJFETs has also been investigated at temperatures from 25 °C to 225 °C. Changes in the on-resistance with temperature are in the range of 0.90~1.33%/°C at zero gate bias and IDS of 50 mA. The threshold voltage becomes more negative with a negative shift of 0.096~0.105%/°C with increasing temperature.