On 26 June 2009, Real Madrid confirmed that Ronaldo would join the club on 1 July 2009 from Manchester United for £80 million (€94 million) becoming the most expensive footballer in history, after agreeing terms and signing a six-year contract. Ronaldo's contract is worth €11 million per year and it has a €1 billion buy-out clause. He was presented to the world media as a Real Madrid player on 6 July, where he was handed the number 9 jersey. The shirt was presented to him by Madrid legend Alfredo Di Stéfano. Ronaldo was welcomed by between 80,000 and 85,000 fans at his presentation at the Santiago Bernabéu Stadium, surpassing Diego Maradona's record of 75,000 fans when he was presented in Italy, after he was transferred from Barcelona to Napoli in 1984. The event was broadcast live on the Spanish and Portuguese public TV stations, RTVE and RTP respectively.
Ronaldo made his Madrid debut on 21 July in a 1-0 win over Shamrock Rovers. His first goal came one week later with a penalty in Madrid's 4-2 win over LDU Quito. On 29 August, Ronaldo capped his La Liga debut with a goal, scoring Real's second from the penalty spot in a 3-2 home win against Deportivo La Coruña. On 15 September, Ronaldo scored two free-kicks in a 5-2 away victory over Zürich, his first Champions League goals for Real. He broke a Madrid club record when he scored in a league match against Villarreal and thus became the first ever player to score in his first four La Liga appearances.
An ankle injury suffered on 10 October, while Ronaldo was on international duty with Portugal against Hungary, kept him out until 25 November, which in turn caused him to miss both of Madrid's Champions League group stage matches against Milan. Ronaldo made his first post-injury start in a 1-0 El Clásico defeat to Barcelona on 29 November. On 6 December, he was sent off for the first time in his Madrid career during Real's 4-2 victory against Almería, a match which also saw him miss a penalty. He was carded first for removing his shirt during a goal celebration, then for kicking out at an opponent three minutes later.
Ronaldo was second in the 2009 FIFA World Player of the Year award and also second in the 2009 Ballon d'Or award. On 5 May 2010, Ronaldo scored his first Real Madrid hat-trick in an away game against Mallorca. Ronaldo and Gonzalo Higuaín scored 53 league goals during the course of the season and became Real's highest scoring league duo in their history.
With the departure of Raúl during the summer of 2010, Ronaldo was handed the number 7 jersey for Real Madrid. On 23 October 2010, Ronaldo scored four goals against Racing de Santander, the most goals he has ever scored in a single match. This completed a goalscoring run of six consecutive matches (three in La Liga, one in the Champions League, and two for Portugal) in which Ronaldo scored in each match, totalling 11 goals, which is the most Ronaldo has scored in a single month. Before Real Madrid's 5-0 defeat by Barcelona at the Camp Nou, Ronaldo scored his second La Liga hat-trick of the season in a 5-1 win over Athletic Bilbao. His final match of the calendar year saw him score a hat-trick in a 8-0 trashing of Levante in the Copa del Rey.
Ronaldo began 2011 with a very promising outlook, especially after Real Madrid acknowledged he had broken numerous goalscoring records, previously settled and held by classic players such as Alfredo Di Stéfano, Hugo Sánchez, and Manuel Alday. Ronaldo began his scoring spree by scoring two vital goals in a tight 3-2 victory away to Getafe. He then consolidated his massive performances by scoring a hat-trick and assisting Kaká to score his first league goal after his return from injury, in a 4-2 victory over Villarreal on 9 January. On 3 March 2011, Ronaldo scored a hat-trick in a 7-0 trashing of Málaga, but was affected by a muscle injury at the end of the match, which forced him to spend 10 days on the sidelines.
In April, he made another massive comeback from injury, sustaining a three-game scoring streak (including two goals in Champions League quarter-finals against Tottenham Hotspur), thus arriving to the first of a historical series of four El Clásico encounters two goals short of breaking his personal record of 42 goals in all competitions in a single season, achieved at Manchester United in the 2007-08 season.
During the second league edition of El Clásico, Ronaldo scored from the penalty spot and took his tally to 41 goals, also taking his scoring streak to four games. On 20 April, Ronaldo scored the winning goal against Barcelona in the 103rd minute of the Copa del Rey final. This goal would later be chosen as both Ronaldo's and Real Madrid's best goal in the season by several fan polls, including those of Marca and Real Madrid's website. 7 May saw Real travel to the Ramón Sánchez Pizjuán to take on Sevilla, where Ronaldo led the thrashing of the Andalusian side, scoring four goals in a 6-2 victory. These four goals took him to 46 for the season which surpassed his previous record of 42 in a season playing for Manchester United. Three days later he reached 49 goals for the season, by scoring another hat-trick in a 4-0 home win against Getafe. On 15 May, after scoring two free-kick goals in a 3-1 win over Villarreal, he equalled the La Liga record with most goals in a season with 38, a record previously held by Telmo Zarra and Hugo Sánchez.