Is supporter a noun

No, the Word "supported" NOT a noun.

The Word "supported" is the past participle, past tense of the verb to support.

The past participle of the verb also functions as an adjective.

Example uses:

Two bamboo poles supported the air conditioner in the window. (verb)

A majority of the students supported the school fundraiser. (verb)

The agency funds supported housing for rehabilitation. (adjective)

The Word support is both a verb and a noun.
The noun 'support' is a Word for a thing that bears the weight of something or keeps it upright; a Word for assistance provided by a company to users of its products; a Word for material or financial assistance; a Word for a thing.

The noun forms of the verb to support are supporter and the gerund, supporting.