Watt and Altuve were recognized for their contributions both on and off the field and for embodying this year's key theme of "Athletes Who Care."
Watt, a defensive end, sustained a season-ending leg injury in Week 5. He finished the year with 11 tackles and two passes defensed, but more important, raised more than $37 million in Hurricane Harvey relief aid.
"All I did was give people a way to help... If I'm going to get an award, I feel like over 200,000 other people should, too," Watt said via a release from Sports Illustrated.
Altuve, the World Series and American League MVP, is a three-time batting champion. He was recognized for giving back and inspiring a community when it needed it most.
"The city of Houston has treated me really good. ... I felt at that time that I owed them something," he said via Sports Illustrated. "So when they were having a hard time, I wanted to give something back to them."
The pair will accept the honor at SI's Sportsperson of the Year Award Show on Tuesday at Barclays Center in New York.
"We will remember 2017 as much for what athletes strove to achieve off the field as for what they achieved on it," said Chris Stone, editorial director of sports at Time Inc. "While J.J. and Jose represent two very different paths, they both led to the same destination: #HoustonStrong.
"This year also marks the 30th anniversary of SI's original 'Athletes Who Care' Sportsperson of the Year honor, which recognizes players who transcended sport alone. This year once again we celebrate a new generation of athletes who care, in all senses of the word: caring about humanitarian efforts, about social and political justice, about their communities and about their crafts."