Until a couple of years ago, the only known examples of Lie groups admitting left-invariant metrics with negative Ricci curvature were either solvable or semisimple. We use a general construction from a previous article of the second named author to produce a large amount of examples with compact Levi factor. Given a compact semisimple real Lie algebra u and a real representation π satisfying some technical properties, the construction returns a metric Lie algebra l(u, π) with negative Ricci operator. In this paper, when u is assumed to be simple, we prove that l(u, π) admits a metric having negative Ricci curvature for all but finitely many finite-dimensional irreducible representations of u⊗ R C, regarded as a real representation of u. We also prove in the last section a more general result where the nilradical is not abelian, as it is in every l(u, π). * Supported by CONICET, FONCYT, and the Alexander von Humboldt Foundation (return fellowship).