He was a former head judge of the singing contest segment "Tawag ng Tanghalan" in a variety noontime show It's Showtime.

He waxed his first single as a solo singer – songwriter with the song "Ako si Superman", which he wrote supposedly for Rico J. Puno.

and "Kahit Maputi na ang Buhok Ko" for Sharon Cuneta as part of the album DJ's Pet, released in 1978.

[3] One of his initial projects as a request from Tito Sotto who was the vice president of the Vicor Music Corporation at that time was to make a song for a twelve-year-old mayor's daughter named Sharon Cuneta.

Sharon stated in a recent interview by Deborah Kan in Star News Asia, that she has been always thankful for and grateful to Rey, for writing her first hit song.

[5] When Sharon Cuneta and her then husband Gabby Concepcion separated, Rey composed the song, "Kahit Wala Ka Na" (Even When You're Gone).

In 1983, Valera faced one of the worst challenges of both his career, and personal life; an impostor was using his name and was committing crimes, among them were car-napping and rape.

[6][7] The list even extended to marrying numerous women, and even petty crimes like "borrowing" money and personal items, all under Rey Valera's name.

Ultimately in 1984, Rey decided to quit show business at the peak of his career to protect his fans and also to make up for the time he lost with his family during his fame.

In May 2008, a friendlier, funnier impostor had emerged on the Filipino television show Bubble Gang, in the persona of comedian/parodist Michael V. He even used "Rey Bolero" as his screen name.

The song, "Kung Kailangan Mo Ako" ( If You Need Me ), was parodied into Kung Kailangan Mo Bato ( If You Need A Stone / To Get Stoned—a slang use of the word "stone", as in illegal substance / getting high ) On 31 October of the same year, Rey Valera, and Michael V. as Rey Bolero (now mimicking Valera's clothes and hairstyle at the time) performed a duet and was one of the highlights of the heavily promoted, "taped as live", two-part Bubble Gang 13th Anniversary special.

Valera's songs are also favorite titles and theme songs of soap operas like Ula, Batang Gubat ("Malayo Pa Ang Umaga"), Sa Sandaling Kailangan Mo Ako ("Kung Kailangan Mo Ako"), Pangako Sa 'Yo ("Pangako") of ABS-CBN.

These include several Sharon Cuneta movies such as Maging Sino Ka Man, Pangako sa 'Yo, Kahit Wala Ka Na, Tayong Dalawa; Sinasamba Kita, Romansa, Hiwalay; Carnap King, Barumbado, and Baby Ama; Pasong Tirad, The Gregorio del Pilar Story, Tampisaw.

[9] He accepted making music for movies and considered it an opportunity, as these projects usually pitted his songwriting skills to follow fresh and often unusual themes and topics, often deviating from pop love songs which he was usually typecast into.

In 2002, Rey reunited with his contemporaries Rico J. Puno and Hajji Alejandro in a series of concerts called "Greatest Hits", highlighting the music of their own time.

[15] In December 2009, Valera is finally inducted to the Philippines Eastwood City Walk of Fame for contributing his singing & composing songs.

Rey once again performed with Rico J. Puno, and Nonoy Zuñiga, along with Claire dela Fuente, Eva Eugenio and Joey Albert at the Philippine International Convention Center under the name, Legends of OPM.

Like its predecessor group, "The Greatest Hitmakers", the concept proved to be a hit, and a repeat performance was done on 5 March of the following year.

He won as the MYX Magna Award 2015 Winner for contributing his success as a composer, guitarist, musical director & singer and also a performer.