Louie Ramírez was born in New York City on February 24, 1938, the son of Puerto Rican parents. He began music studies in his teens and made his professional debut in 1956 by taking the vibraphone chair in Joe Loco's band from Pete Terrace. His first recording, with Loco for Ansonia, followed in 1957. A few years later his writing was already on the Latin dance floor: he is credited as a writer of "El Güiro de Macorina," a Johnny Pacheco number on Pacheco y su Charanga (Alegre, 1961), the year he also played percussion on Sabu Martínez's Sabu's Jazz Españole (Alegre LPA 802). The salsa and Latin dance music of New York's Puerto Rican neighborhoods was his working world for the rest of his life, and most of what he made was salsa, boogaloo and romantic dance-band music, with Latin jazz as a vibraphone-led side of the same career.

His first record as a leader was Introducing Louie Ramírez (Remo, LPR 1512, 1964), a program of pachanga, bolero, son montuno, cha-cha-cha, descarga and guaguancó with Ramírez on timbales and vibraphone, Sabu Martínez on bongos, Bobby Valentín and Larry Spencer on trumpets and Chivirico Dávila and Victor Velázquez singing. From 1965 to 1968 he worked closely with Charlie Palmieri and Joe Cuba. He played timbales on Palmieri's boogaloo album Latin Bugalu (Atlantic, 1968), wrote "I'm Insane" for the Joe Cuba Sextet's My Man Speedy! (Tico, 1968), and made Vibes Galore (Alegre LPA 845, 1966) with his Conjunto Changó, an album of vibraphone-led dance music that includes his tune "El Títere." In 1967 Mercury issued the boogaloo album In the Heart of Spanish Harlem (SR 61121), arranged by Ramírez with Richard Marin producing and bilingual track titles on the sleeve.

Fania released Ali Baba (Fania LP 357, 1968) with him billed under that pseudonym; the label's own history says the alias was a way around an earlier recording commitment. Jerry Masucci produced and Pacheco was the recording director. Ramírez arranged and played timbales, Rudy Calzado sang the Spanish lyrics and Bobby Marín the English ones, and Ramírez wrote six of the nine tracks, "El Títere" among them. He and the singer Pete Bonet, formerly with Ray Barretto's band, then made records as Pete & Louie, including the album Pete & Louie (Fania LP 390, 1970), which streaming services carry as The Beautiful People. In 1972 he arranged En Algo Nuevo for the singer Tito Rodríguez (TR Records), and in 1974 he produced and arranged his own Típico for UA Latino with the singer Victor Velázquez. He also wrote the arrangement of "La Familia" on Barretto's Indestructible (Fania, 1973).

In 1975 he became a staff producer at Fania, and the decade's New York salsa records are full of his name in the production credit. Discogs lists him as producer of albums by Joe Cuba, Kako, Típica '73, Sonora Ponceña, Ricardo Ray and Bobby Cruz, Vítin Avilés, La Lupe, Orquesta Novél and Chocolate Armenteros, among many others, and of the Fania All Stars' Tribute to Tito Rodríguez (1976), on which he also arranged three tracks. He arranged two pieces for Héctor Lavoe's La Voz (Fania, 1975) and wrote and arranged "Los Bravos" for the All Stars' Cross Over (Columbia, 1979). For Tito Puente he produced The Legend (Tico, 1977) and the Beny Moré tribute Homenaje a Beny (Tico, 1978). Fania's history says he also performed with the Fania All Stars on their international tours. The trade gave him a nickname that stuck, "the Quincy Jones of salsa."

His own albums at Cotique, a label that came into the Fania group, were more adventurous than the production work. A Different Shade of Black (Cotique CS 1085, 1976) is a crossover record with Bernard Purdie on drums, Cornell Dupree on guitar and Paul Griffin on piano. Marty Sheller wrote most of the charts, and the program includes "Salsa," "Latin Rhapsody" and a version of "Do It Any Way You Wanna." Louie Ramírez y Sus Amigos (Cotique JMCS-1096, 1978) adds a Moog synthesizer and the Selwart Clarke Strings, covers two Beatles songs, "Something" and "Because" (the latter as a danzón), and opens with "Paula C," a song by Rubén Blades. Salsa Progresiva (Cotique JMCS-1100, 1979) has Tito Allen, Adalberto Santiago and Angela Bofill on backing vocals and turns "Stella by Starlight" into a guaguancó. Salsero (Cotique JMCS 1104, 1980) has him on timbales, vibraphone and piano.

The 1980s belong to his partnership with the singer Ray De La Paz. He produced Noche Caliente: Los Éxitos Más Románticos de Ayer en Ritmo de Salsa (K-Tel, 1982), a set of romantic ballads in salsa arrangements issued under the name Noche Caliente, which is often cited as a starting point for the romantic salsa wave. Their Caiman albums followed: Con Caché (Caiman CLP-9004, 1984), Alegres y Románticos (Caiman 9011, 1985, with Pacheco among the chorus) and Sabor con Clase (Caiman CLP-9019, 1986), each credited to Ramírez and De La Paz together. In 1986 he paid tribute to the vibraphonist Cal Tjader on the Latin jazz album A Tribute to Cal Tjader (Caiman CLP 9025). He plays vibraphone, timbales and synthesizer, arranged and produced it, and has Paquito D'Rivera on alto saxophone. Later albums included El Genio (1989), Sexy Salsa (1989), a second Louie Ramírez y Sus Amigos (1990) and The King of Latin Vibes (Sugar, 1991), with Carlos "Patato" Valdés on congas. A photograph from the 1980s shows him at the Village Gate in Manhattan, where Monday nights were billed as "Salsa Meets Jazz," playing vibraphone beside Tito Puente and the vibraphonist Warren Chiasson.

He passed away on June 7, 1993, at 55, after a heart attack while driving on Junction Boulevard in Queens. He was recording his third album with Ray De La Paz, Prepárate Bailador, which RMM released later that year.

Ramírez was a bandleader and arranger first and a vibraphone soloist second. The records that made his reputation are dance records: charanga-era descargas, boogaloo, hard-driving Fania salsa and, in the 1980s, the smoother romantic salsa he made with Ray De La Paz. His reputation as "the Quincy Jones of salsa" rests on that behind-the-scenes arranging and producing for other bandleaders more than on any one solo.

The jazz side is real but smaller. His vibraphone career began in Joe Loco's New York Latin band rather than in a bebop group, and his vibes lines sit inside the clave-based vocabulary he worked in. The clearest jazz documents are Vibes Galore, A Tribute to Cal Tjader, in which he plays the repertoire of Cal Tjader ("Soul Sauce," "Mambo for Cal," "Lullaby of Birdland") over a Latin rhythm section, and The King of Latin Vibes. A Different Shade of Black shows a third direction, a salsa-and-funk crossover with American studio players. He was a bridge figure, a musician working inside the salsa industry who kept returning to the vibraphone and to jazz repertoire when the label allowed it.