Born in São Paulo, Diogo started his football career at Associação Portuguesa de Desportos. He quickly made a name for himself at the club, breaking into the first team in 2007 and contributing largely to a promotion to the Série A, scoring 18 goals in 28 games – season's best – and being voted the competition's best player. It was this form which initially prompted Brazilian under-20 coach Nélson Rodrigues to include Diogo in his team. In 2008 he had his first taste of top-flight football with Portuguesa, and showed early good form with six goals in 13 matches. Early in the same year, president Manuel da Lupa said he was as good as if not better than A.C. Milan’s teenage sensation Alexandre Pato; he added that the player had only shown 50% of his capability due to consistent injuries. In July 2008, several teams had been attracted to Diogo's talents, and the player revealed his desire to play his trade in Europe after longtime admirers Arsenal were joined by ACF Fiorentina in bidding for his services. He had been monitored by the former's scouting department for more than two years, and offers included a £9,000,000 one, promptly rejected by Portuguesa; Arsenal manager Arsène Wenger also publicly stated that he had tried to sign him once, as a 16-year-old.
Olympiakos
also became interested and, in a widely-documented and somewhat controversial period of negotiation, Diogo finally signed for the Greek club in August 2008, for €9 million and 70% of the player's rights. Arriving in Athens on the 19th he passed his medical the following day and, on 21 August, signed a five-year contract. Diogo made his first appearance in the season's opener, against Asteras Tripoli F.C. on 30 August 2008. On 6 September he scored from the penalty spot against Ionikos FC, in a friendly match. In the second round, he netted the game's only goal at Skoda Xanthi FC; during his first campaign he also showcased his good heading ability by scoring many of his goals from headers, being at one point the player with more goals with that specific body part at four. In the 2008–09 UEFA Cup, Diogo scored twice in the 5–0 home triumph against FC Nordsjælland on 2 October, adding two more in a 5–1 home win over S.L. Benfica in the following month, also in the group stage. Hence, heightened rumours of a big-money transfer to Europe's elite – and again to England – surfaced, whilst the player was ranked seventh in The Daily Telegraph's list of Footballers Transfer Target List; eventually, the Piraeus team won the double. Further interest arose in October 2008, now from three other Premier League clubs, Middlesbrough, Chelsea and Liverpool. The latter's coach, Rafa Benítez, again declared interest in the player in March of the following year, preparing to offer £12 million to acquire his services. Anfield scouts had been said to have checked on him, seeing him as a perfect replacement for departed Robbie Keane; Benítez then loaned Sebastián Leto to Olympiacos, further fueling rumours that the player would be included in a swap deal, but nothing came to fruition, with Leto instead moving to Panathinaikos FC. Diogo's second season was disastrous for both him and the team, suffering several injuries which limited to just slightly more than half of the games, scoring just two goals and losing his place in the starting lineup to Kostantinos Mitroglou. He started 2010–11 by netting twice against Besa Kavajë of Albania in a 5–0 away win for the UEFA Europa League; in the competition's next round, however, against Maccabi Tel Aviv FC, he was sent off after punching opposing goalkeeperLiran Strauber, in a 0–1 away loss that also meant the Greeks' elimination on the away goals rule.
Back to Brazil
Diogo returned to Brazil on 19 August 2010, being loaned to Clube de Regatas do Flamengo. Six months later he joined Santos FC also on loan, failing to perform overall and returning to Olympiakos in January 2012, being excluded from the first team late into that year. On 6 March 2013, Diogo returned to his first club Portuguesa.
Buriram United
On 31 December 2014, Diogo signed a two-year contract with Buriram United F.C. from the Thai Premier League. He scored in his debut on 24 January 2015, helping his new team defeat Bangkok Glass F.C. 1–0 in the Kor Royal Cup. In his first season, Diogo scored 45 goals in 51 games all competitions comprised, as Buriram became the first Asian club to win five titles in one year.
Johor Darul Ta'zim
On 3 January2019, Johor Darul Ta'zim F.C. announced the signing of Diogo for an approximate fee of €1.5 million, the highest ever paid by a Malaysian club.
