Lasker's match record was as impressive between his 1896–1897 re-match with Steinitz and 1914: he won all but one of his normal matches, and three of those were convincing defenses of his title. He first faced Marshall in the World Chess Championship 1907, when despite his aggressive style, Marshall could not win a single game, losing eight and drawing seven (final score: 11½−3½).

He then played Tarrasch in the World Chess Championship 1908, first at Düsseldorf then at Munich. Tarrasch firmly believed the game of chess was governed by a precise set of principles. For him the strength of a chess move was in its logic, not in its efficiency. Because of his stubborn principles he considered Lasker as a coffeehouse player who won his games only thanks to dubious tricks, while Lasker mocked the arrogance of Tarrasch who, in his opinion, shone more in salons than at the chessboard. At the opening ceremony, Tarrasch refused to talk to Lasker, only saying:"Mr. Lasker, I have only three words to say to you: check and mate !"

Lasker gave a brilliant answer on the chessboard, winning four of the first five games, and playing a type of chess Tarrasch could not understand. For example, in the second game after 19 moves arose a situation (see diagram at left) in which Lasker was a pawn down, with a bad bishop and doubled pawns. At this point it appeared Tarrasch was winning, but 20 moves later he was forced to resign. Lasker eventually won by 10½−5½ (eight wins, five draws, and three losses). Tarrasch claimed the wet weather was the cause of his defeat.

In 1909 Lasker drew a short match (two wins, two losses) against Dawid Janowski, an all-out attacking Polish expatriate. Several months later they played a longer match, and chess historians still debate whether this was for the World Chess Championship. Understanding Janowski's style, Lasker chose to defend solidly so that Janowski unleashed his attacks too soon and left himself vulnerable. Lasker easily won the match 8–2 (seven wins, two draws, one loss). This victory was convincing for everyone but Janowski, who asked for a revenge match. Lasker accepted and they played World Chess Championship match in Paris in November–December 1910. Lasker crushed his opponent, winning 9½−1½ (eight wins, three draws, no losses). Janowski was not able to understand Lasker's moves, and after his first three losses he declared to Edward Lasker, "Your homonym plays so stupidly that I cannot even look at the chessboard when he thinks. I am afraid I will not do anything good in this match."

Between his two matches against Janowski, Lasker arranged another World Chess Championship in January–February 1910 against Carl Schlechter. Schlechter was a modest gentleman, who was generally unlikely to win the major chess tournaments by his peaceful inclination, his lack of aggressiveness and his willingness to accept most draw offers from his opponents (about 80% of his games finished by a draw). The conditions of the match against Lasker are still debated among chess historians, but it seems Schlechter accepted to play under very unfavourable conditions, notably that he would need to finish two points ahead of Lasker to be declared the winner of the match, and he would need to win a revenge match to be declared World Champion. The match was originally meant to consist of 30 games, but when it became obvious that there were insufficient funds (Lasker demanded a fee of 1,000 marks per game played), the number of games was reduced to ten, making the margin of two points all the more difficult.

At the beginning, Lasker tried to attack but Schlechter had no difficulty defending, so that the first four games finished in draws. In the fifth game Lasker had a big advantage, but committed a blunder that cost him the game. Hence at the middle of the match Schlechter was one point ahead. The next four games were drawn, despite fierce play from both players. In the sixth Schlechter managed to draw a game being a pawn down. In the seventh Lasker nearly lost because of a beautiful exchange sacrifice from Schlechter. In the ninth only a blunder from Lasker allowed Schlechter to draw a lost ending. The score before the last game was thus 5–4 for Schlechter. In the tenth game Schlechter tried to win tactically and took a big advantage, but he missed a clear win at the 35th move, continued to take increasing risks and finished by losing. Hence the match was a draw and Lasker remained World Champion.

In 1911 Lasker received a challenge for a world title match against the rising star José Raúl Capablanca. Lasker was unwilling to play the traditional "first to win ten games" type of match in the semi-tropical conditions of Havana, especially as drawn games were becoming more frequent and the match might last for over six months. He therefore made a counter-proposal: if neither player had a lead of at least two games by the end of the match, it should be considered a draw; the match should be limited to the best of thirty games, counting draws; except that if either player won six games and led by at least two games before thirty games were completed, he should be declared the winner; the champion should decide the venue and stakes, and should have the exclusive right to publish the games; the challenger should deposit a forfeit of US $2,000 (equivalent to over $194,000 in 2006 values); the time limit should be twelve moves per hour; play should be limited to two sessions of 2½ hours each per day, five days a week. Capablanca objected to the time limit, the short playing times, the thirty-game limit, and especially the requirement that he must win by two games to claim the title, which he regarded as unfair. Lasker took offence at the terms in which Capablanca criticized the two-game lead condition and broke off negotiations, and until 1914 Lasker and Capablanca were not on speaking terms. However, at the 1914 St. Petersburg tournament, Capablanca proposed a set of rules for the conduct of World Championship matches, which were accepted by all the leading players including Lasker.

Late in 1912 Lasker entered into negotiations for a world title match with Akiba Rubinstein, whose tournament record for the previous few years had been on a par with Lasker's and a little ahead of Capablanca's. The two players agreed to play a match if Rubinstein could raise the funds, but Rubinstein had few rich friends to back him and the match was never played. The start of World War I put an end to hopes that Lasker would play either Rubinstein or Capablanca for the World Championship in the near future. Throughout World War I (1914–1918) Lasker played in only two serious chess events. He convincingly won (5½−½) a non-title match against Tarrasch in 1916. In September–October 1918, shortly before the armistice, he won a quadrangular (four-player) tournament, half a point ahead of Rubinstein.

Despite his superb playing results, chess was not Lasker's only interest. His parents recognized his intellectual talents, especially for mathematics, and sent the adolescent Emanuel to study in Berlin (where he found he also had a talent for chess). Lasker gained his abitur (high school graduation certificate) at Landsberg an der Warthe, now a Polish town named Gorzów Wielkopolski but then part of Prussia. He then studied mathematics and philosophy at the universities in Berlin, Göttingen and Heidelberg.