If I completed SGTs course and CPLs course while in the Marine Corps, will I have to attend BLC and ALC in the Army as a Sgt to pick up?

Sgt Michael Reyes - Officially, a Marine Corporal does the Job of a Sergeant in the Army. Army Sergeants lead fire teams, Corporals lead them in the Marines. While a Marine Corporal may be assigned as Squad leader, the position in the Marines is an E-5 slot. The reason that you see so many Marines serving in positions above their pay scale is the Marine promotion system takes much longer to make rank. No limit on ranks through E-4 in the Army, so those ranks don't require slots and a soldier will normally make E-4 in two years if they get their schools. You can make Sergeant in less than three years since they can waiver TIS and TIG, but three years in service and at least eight months in grade are the normal requirements .

CPT Lawrence Cable

Correction: In the Combat Arms fields: USMC Corporals (E-4) routinely hold billets in the USMC that Staff Sergeants (E-6) in the Army hold. USMC sergeants (E-5) routinely hold billets in the USMC that Sergeants First Class (E-7) holds in the Army.

I know this because I (and many, many others in the Corps) held these billets which require high levels of responsibility!

According to AR 600-8-19 Para 7-24 a(4) and a(5) 16MAY2019
USMC NCO Course and Basic NCO courses are equivelant. Corporal IS the first and "basic NCO" of the Marine Corps, carrying the same duties and level of responsibility as an Army Sergeant.
I just completed a packet for another prior service Marine who joined my unit and got him the credit for BLC.

Yeah, I don’t believe that at all SGM. You’re the first person who’s said that. I have all my official documents from Cpls course and Sgts course, gave them to my recruiter and was told I’m exempt from ALC.