SoftBank reported a record 745 billion yen ($7.59 billion) operating profit for the year ended on March 31, up 10 percent from the previous year, and Son forecast a further rise this year to between 800 billion and 900 billion yen.
The Japanese mobile operator announced its deal for Sprint last October as it looks for growth abroad. The company faces a stagnating market at home, crowded by large competitors such as NTT DoCoMo and KDDI Corp.
Son said U.S. regulatory review of the deal was on schedule and reiterated that the offer was on track to close by July 1.
The Japanese company received support for the deal from Intel Chief Executive Paul Otellini, who wrote to the Federal Communications Commission saying Son's vision to build a high-speed U.S. national network was compelling.
"We need this competition in the wireless space as the AT&T/Verizon model is not giving that to consumers at this time," Otellini said.
U.S. satellite TV provider Dish has offered $25.5 billion for Sprint, aiming to tap the company's wireless network to offer services that would let U.S. consumers watch video anywhere, anytime.
Sprint said on Monday that SoftBank has waived some terms of their agreement so that Sprint can seek more information from Dish.
Analysts and sources say Son is unlikely to walk away from Sprint, with SoftBank's lenders open to providing additional financing if the company decides to raise its bid.
Sprint has set June 12 as the tentative date for a special meeting for shareholders to vote on the proposed deal with SoftBank.
SoftBank's shares ended 1.2 percent higher on Tuesday, before Son's comments, compared with a 0.2 percent dip in Tokyo's benchmark Nikkei average. Although the shares lost nearly one-fourth of their value in the two days after the Sprint deal was announced, they have since rebounded and are up 67 percent since that time, in line with the Nikkei's 62 percent surge.