He played college basketball for the University of the Visayas (UV) Green Lancers, winning the Cebu Schools Athletic Foundation, Inc. (CESAFI) men's basketball title in each of his 5 years with UV, as well as winning two MVP awards in 2003 and 2004.

Quiñahan was dubbed "Baby Shaq" in the Philippine Basketball League where he played for the Granny Goose team not just because of his physical resemblance to the former Los Angeles Lakers center Shaquille O'Neal, but because of his dominant presence inside.

[1] In his rookie year in the PBA with Alaska, Quiñahan averaged 2.9 points, 2.7 rebounds, and 9.7 minutes in 39 games.

[5] In March 2010, him, Mark Yee, and Aaron Aban was traded by Air21 (formerly Burger King) to the Talk 'N Text Tropang Texters for Yancy de Ocampo and Ren-Ren Ritualo.

[8] On August 26, 2011, Quiñahan and Norman Gonzales were traded to Rain or Shine Elasto Painters for Doug Kramer and Josh Vanlandingham.

In the Philippine Cup, he contributed to Rain or Shine hitting a franchise-record 22 three pointers in a win over Meralco.

[20] Against Meralco, he made the game-winning three pointer that gave Rain or Shine its sixth straight win, a franchise record.

[26] Quiñahan began the 2015–16 PBA season with a game-high 17 points along with eight rebounds and four blocks in a win over the Star Hotshots.

[35] He led the team in scoring once again in a win over the Blackwater Elite with 15 off the bench as their burly import Pierre Henderson-Niles made his debut.

[38] In game 6, he and Raymond Almazan combined for 29 points to get Rain or Shine's second championship in franchise history.

[42] On October 13, 2016, Quiñahan was traded by the Rain or Shine Elasto Painters to the GlobalPort Batang Pier in exchange for Jay Washington.

[48] On May 6, 2017, Quiñahan was traded again, this time to the NLEX Road Warriors along with Larry Fonacier as part of a four-team trade between the Road Warriors, GlobalPort, Meralco and TNT that also involved Garvo Lanete sent to the Bolts, Anthony Semerad to the KaTropa and Bradwyn Guinto, Sean Anthony and Jonathan Grey all to the Batang Pier.

[54] In a Christmas Day win over GlobalPort during the 2017–18 Philippine Cup, Quiñahan contributed 19 points and nine rebounds.

[57] A loss to TNT (despite his 20 points and seven rebounds) gave NLEX a record of 6–5, good to make the playoffs.

[69] He started the season alongside a debuting Poy Erram and Alas, who was returning after his ACL injury.

[71] They got a win against the Bolts, in which he had 16 points (including a clutch free throw with 31 seconds left in the game).

[74] It was then revealed that he had been playing through a meniscal tear on his right knee, as the team was without star guards Alas and Kiefer Ravena for a lengthy period of time due to another ACL injury and a FIBA suspension respectively.

[76] He then was crucial in NLEX completing a 26-point comeback win over the Hotshots with his 14 points and eight rebounds, that led to Jericho Cruz's game-winning putback.

[77] NLEX won five straight games before a loss to the Batang Pier, in which Alas returned from his injury.

[79] They faced the Batang Pier in the first round, where NLEX lost despite his 20 points as his teammates Erram and Paul Varilla were ejected from the game.

[81] Quiñahan started the 2020 season with a game and career-high 26 points in a loss to Ginebra, although he didn't finish the game due to being ejected in the third quarter for a flagrant foul for hitting Ginebra's Stanley Pringle in the face and a technical foul for arguing with a referee.

[85] NLEX then won over the league-leading TNT, but he was given a flagrant foul after an altercation with Bobby Ray Parks Jr. near the end of the game.

[106] After the Philippine Cup, Coach Guiao parted ways with NLEX, and was eventually replaced by Frankie Lim.

[113] As of the end of 2022–23 season[114][115] Quiñahan represented the Philippines in the 2017 FIBA 3x3 World Cup on June 17 to 21, 2017 in Nantes, France.

[117] A 6 ft 6 in (1.98 m) slotman who loves to use his heft to be effective inside the paint, Quiñahan also has a decent stroke from the outside and can consistently hit the open jumper from any distance.

[1][118] In 2012, Quiñahan married longtime partner Eunice Llanos while Rain or Shine was in the Philippine Cup semifinals.