LeBron James blocked his most shots in a game on March 16, 2004 and on February 23, 2004, with 5 blocks.

lebron james career high in blocks
Interpreted as:
LeBron James career high in blocks in a regular-season game
3/16/2004James2/23/2004James1/15/2018James10/25/2017James3/27/2013James12/18/2012James2/18/2010James1/29/2010James1/11/2010James10/27/2009James11/7/2008James11/4/2007James2/15/2006James2/26/2021James12/15/2019James11/14/2018James3/15/2018James3/9/2018James11/24/2017James11/13/2017James2/23/2017James12/29/2016James12/8/2015James55444444444443333333333
NAMEDATETMOPPBLKMINPTSREBASTSTLTOVFGMFGAFG%3PM3PA3P%FTMFTAFT%PF+/-
LeBron JamesLeBron James3/16/2004CLECLEvsCHICHI53217580451631.32366.75862.51+24
LeBron JamesLeBron James2/23/2004CLECLEvsNOHNOH53621462171643.81520.066100.03+4
LeBron JamesLeBron James1/15/2018CLECLEvsGSWGSW436328638121866.7020.081361.53-14
LeBron JamesLeBron James10/25/2017CLECLE@BKNBKN44129101308122060.01250.04850.01-2
LeBron JamesLeBron James3/27/2013MIAMIA@CHICHI440327324111764.72540.081172.71+2
LeBron JamesLeBron James12/18/2012MIAMIAvsMINMIN442226111081844.42540.04580.00+12
LeBron JamesLeBron James2/18/2010CLECLEvsDENDEN44743131523153345.51911.1121770.61-5
LeBron JamesLeBron James1/29/2010CLECLE@INDIND436229132561833.3040.0101758.82+22
LeBron JamesLeBron James1/11/2010CLECLE@GSWGSW4423781122122352.21425.0121485.71+12
LeBron JamesLeBron James10/27/2009CLECLEvsBOSBOS445384825122254.54944.4101376.940
LeBron JamesLeBron James11/7/2008CLECLEvsINDIND439279814112445.81616.74757.12-3
LeBron JamesLeBron James11/4/2007CLECLE@PHXPHX443275823112642.33560.022100.00-18
LeBron JamesLeBron James2/15/2006CLECLE@BOSBOS45443121122163250.0050.0111573.35+5
LeBron JamesLeBron James2/26/2021LALLALvsPORPOR3362811742112152.42540.04850.01+9
LeBron JamesLeBron James12/15/2019LALLAL@ATLATL3373213714122157.141040.04757.11+10
LeBron JamesLeBron James11/14/2018LALLALvsPORPOR3364410914131968.45683.3131586.70+4
LeBron JamesLeBron James3/15/2018CLECLE@PORPOR3413514626152560.01425.04944.44-3
LeBron JamesLeBron James3/9/2018CLECLE@LACLAC3392510625112055.03742.9020.02-16
LeBron JamesLeBron James11/24/2017CLECLEvsCHACHA34027161303102050.03837.54757.12-2
LeBron JamesLeBron James11/13/2017CLECLE@NYKNYK336239120571450.02450.071070.01+2
LeBron JamesLeBron James2/23/2017CLECLEvsNYKNYK3371813150671163.6020.04666.71+10
LeBron JamesLeBron James12/29/2016CLECLEvsBOSBOS344238111891850.02633.33742.92+1
LeBron JamesLeBron James12/8/2015CLECLEvsPORPOR3403310322142458.31333.344100.03+7
LeBron JamesLeBron James11/14/2015CLECLE@MILMIL3453712517132748.151145.561250.03-2
LeBron JamesLeBron James4/2/2015CLECLEvsMIAMIA33523871391656.31250.04580.03+14
Results may be incomplete. StatMuse has complete game-level data for blocks going back to the 1983-84 season.