Born in Conceição do Araguaia, Brazil, Welliton started his career playing for the Brazilian side Goiás. In December 2005, Welliton signed his first professional contract with the club, keeping him until 2009. Shortly after signing his professional contract, Welliton was loaned out to Ituano. After scoring sixteen goals in thirty-appearance, Welliton re-established himself in the first team at Goiás.
In July 2007 he moved to Russian club Spartak Moscow, signing a five-year contract. Welliton was previously linked with a move to Lokomotiv Moscow, Dynamo Kyiv and Dynamo Moscow.
Welliton made his Spartak Moscow debut on 5 August 2007, in a 3-2 win over Tom Tomsk. However, in the next match against Krylia Sovetov Samara, Welliton was a subject of racism by opposition fans, telling him to go home. Welliton was defended by Spartak Moscow and criticised the racism as a disgrace. He then scored his first Spartak Moscow goal, in a 3-1 lost against Rubin Kazan on 25 August 2007. Welliton was then suffered an injury during a match against CSKA Moscow, resulting him being substituted. After the match, it was reported that Welliton was sideline for about three weeks. He added three more goals later in the season, where he finished the half of the season at Spartak Moscow, making twelve appearance and scoring four times. For the first four months at the club, Welliton spoke out his life in Russia.
To begin the 2008 season, Welliton scored six times in his first nine matches. Former Russia midfielder Aleksandr Mostovoi heaped praise on the young striker after his performance in a 3–0 away win, stating "He has overcome all problems with passage into a new country. He is young, fast, technical, an ideal artist who acts along the entire front line of attack, not just along the flanks as this past season." Unfortunately, his stellar start was cut short due to a muscle tear that forced him out of action for 10 months.
After a successful return in 2009, Welliton made his return from taining and played his first match for Spartak Moscow since returning from injury, in a 1-1 draw against Zenit Saint Petersburg. Three weeks later, Welliton then scored his first Spartak Moscow goal, in a 2-0 win over Spartak Nalchik By the time he scored eleven times in sixteen appearance, He scored his first career hat-trick on 8 August 2009 at Spartak Nalchik. His excellent performance in his second season at Spartak Moscow also rewarded him with a long term contract with Spartak Moscow. Later in the 2009 season, Welliton helped Spartak Moscow early to a prime position to qualify for the UEFA Champions League after finishing a dismal 8th place in 2008. He also finished the season as the league's top scorer for 2009 season, with twenty-one goals.
In the 2010 season, Welliton started the season with his goalscoring form continued to impress. However, His excellent form has continued into the 2010 Russian Premier League Season as he again became the top scorer, this time with 19 goals. He started he first half of the season well, scoring seven goals in ten appearance, including scoring a brace against Anzhi Makhachkala on 6 May 2010. However, he was sidelined for three weeks after injuring his ligaments of the ankle joint of the left leg during a match against Metallurg Lipetsk in the fifth round of Russian Cup. After making his return in the field against CSKA Moscow, Welliton scored two consecutive hat-tricks. On 15 August he netted three goals in an away game against Russian rivals Lokomotiv Moscow, which ended 2–3. On 21 August 2010, he scored another hat-trick, this time against FC Tom Tomsk in a 4–2 win at home. The latter was scored just in 6 minutes and became the fastest hat-trick in the entire history of Russia. Because of this, Welliton's performance attracted interests from clubs around Europe, including La Liga side RCD Mallorca. Despite this, Welliton was able to finished the season as the league's top scorer for 2010 for the second time running, with nineteen goals. Elsewhere, He scored six goals in the final seven matches to secure the scoring title and a berth in the 2010–11 UEFA Champions League group stage for Moscow, where he scored against Marseille However, Welliton was sent-off in the last game of the group stage against Marseille when he involved in an incident with Souleymane Diawara, resulting his sending off. At the end of the season, Welliton was awarded the club's Player of the Year.
In the 2011-12 season proved to be decline at Spartak Moscow when he suffered injuries at the start of the season. It started off when he injured his heel in training. After making his return, Welliton scored against Ajax in the return leg of last 16 of Europa League, with a 3-0 win and then against Volga Nizhny Novgorod in the league. However, his return was short-lived when he injured his adductors in training. After making his return briefly, where at one point, he was captain during the match against Spartak Nalchik, his return was short-lived once again when he suffered a hamstring injury during a match against CSKA Moscow, requiring operation. Despite interests from Rubin Kazan and Wolfsburg, Welliton remained at the club. After making his return, Welliton then scored four goals between 26 June 2011 and 8 July 2011 before adding another on 28 August 2011 against CSKA Moscow. But during the match, Welliton collided with Igor Akinfeev, which resulted Welliton being booked. Initially given six match ban, this was reduced to a three match via Spartak's appeal. After returning from suspension, Welliton continued to suffered injuries when he hurt his back in late-October and fractured his collarbone after colliding with Vasili Berezutski during a match on 19 March 2012, which saw him sidelined for the rest of the season. Welliton ended his 2011-12 season, with 21 appearance and scoring seven times.
In the 2012-13 season, Welliton made his return from injury, where he was included in the opening game of the season against Alania Vladikavkaz. But Welliton's injury problem haunt him once again when he was injured his thigh during the match against Terek Grozny, resulting him sidelined for weeks. Welliton was left out of the squad and eventually fallen out with Unai Emery with lack of effort in training and performance. As a result, Welliton attracted further interests from Metalist Kharkiv, Rubin Kazan, Flamengo and Fenerbahçe.
During his seven years career at Spartak Moscow, Welliton made 132 appearance and scoring sixty-one times.
On 6 February 2013, Welliton was loaned to Brazilian club Grêmio. Welliton made his Grêmio debut on 14 February 2013, coming on as a substitute for Eduardo Vargas in the 73rd minutes, in a 2-1 loss against Huachipato in group stage of Copa Libertadores. It wasn't until 26 May 2013 when Welliton made his league debut in the opening game of the season, coming on as a substitute for Hernán Barcos, in a 2-0 win over Náutico. However, Welliton made only ten appearance in tall competition, as he struggled to score.
He moved to São Paulo later. With a few players available on transfer market, Paulo Autuori praised Welliton as a new hiring for his club. According to Autuori, Welliton "has the profile what we are looking for, with balance and presence to score goals. He can play as a winger or a center forward." To carry out the transfer, São Paulo managed to reach a complex agreement with Grêmio. It involved some benefits for Grêmio on Rhodolfo's loan contract, and stipulated that the side from São Paulo would pay half of his salary (R$200,000), the rest went to the side from Porto Alegre. After making his debut as a substitute against Botafogo on 1 September 2013, Welliton scored his first goal two weeks later on 19 September 2013, in a 1-0 win over Atlético Mineiro. Welliton later added two more goals later in the season against Náutico and Fluminense. After making nineteen appearance and scoring four times, the club was ken to sign him permanent, but eventually decided against over the price tag.
On 31 January 2014 he was loaned to Celta de Vigo in La Liga until the end of the season. Because of his actions, Welliton was given a maximum fine by the club. However, his time at Celta Viga was forgettable, as Welliton made only one appearance, coming on as a substitute in the 87th minutes against Elche. To make things worst, Welliton suffered a hamstring injury that sidelined him rest of the season.
On 20 August 2014, Welliton moved to the Turkish side Mersin İdmanyurdu, signing a two-year contract. Spartak Moscow reportedly received around €1 million from the transfer.
After being on the bench for the first two matches, Welliton made his Mersin İdmanyurdu debut as a substitute in a 2-0 win over Çaykur Rizespor on 20 September 2014. Four days later, Welliton scored his first goal for the club, in the second round of Turkish Cup, in a 3-0 win over Kemer Tekirovaspor. It wasn't until 8 November 2014 for Welliton score his first league goal for the club, in a 2-1 win over Balıkesirspor, followed up his second in the next game two weeks later against Akhisar Belediyespor. Welliton then scored his first hat-trick for the club and providing two assists in a 6-2 win over Kasımpaşa. Towards the end of the season, Welliton later added four more goals against Balikesirspor, Konyaspor, Gençlerbirliği and İstanbul Başakşehir. In his first season at Mersin İdmanyurdu, Welliton made thirty-four appearance and scoring thirteen goals in all competitions.
In the 2015-16 season, Welliton scored two goals in two consecutive matches against Kayserispor and Galatasaray despite the clu's poor start following three losses to the start of the season. Welliton later scored two goals in two consecutive matches for the second time against Eskişehirspor and Çaykur Rizespor. Though he scored six goals in twenty-one appearance, Welliton's injury problem became the club's problem, resulting their relegation.
Following Mersin İdmanyurdu relegation to TFF First League, Welliton's future was in doubt, as his contract expires on 30 June 2016.
On July 1, 2016 Welliton signed a two-year contract with Kayserispor
Welliton has not been called up by Brazil and has expressed interest in representing Russia. Having been playing for Russia for over three years, Welliton said it would be an honour to play for the national team, citing his preparation as a reason. However, a decision to play for Russia has met with a mixed reception. However, Welliton's decision to play for Russia has met with a mixed reception, with the club's captain Andrey Arshavin and Leonid Fedun argued against to have Welliton to be in the squad, while the president of Russian Football Union, Sergey Fursenko, argued for Welliton to be in the squad.
In November 2011 Spartak Moscow announced they were in the process of helping Welliton acquire a Russian passport. Should Welliton represented the Russia national team, he would be the first foreigner footballer born outside of Russia to do so. However, the process of never happened.Goiás
Goiás State League: 2006
Russian Premier League top scorer (2): 2009 (21 goals), 2010 (19 goals)
In May 2014, Welliton was arrested for driving under influence in Spain. Welliton was charged and had his driving revoked, in addition, of 9000 euros.
On 27 July 2007, Welliton became a father when his wife, Monica, gave birth to a son, Kayu. Welliton and Monica were married when they were sixteen. Welliton also has a tattoo on his left arm with his mother name, Yolanda. However, in an interview with Sport Express, Welliton and his wife have since been separated and his wife returned to Brazil. Welliton also revealed he grew up in poor family and has a youngster sister and two older brothers.