Cross-laminated timber (CLT) is an engineered wood material that was introduced in the last decade as a promising candidate for building wood structures higher than 10 stories. Thus far, a handful of tall residential CLT buildings have been built in low seismic regions around the world. Previous full-scale seismic shaking table tests of multistory CLT buildings revealed that this system is susceptible to overturning damage as a result of lateral seismic loads. To effectively resist overturning, a new floor connection detail was proposed to engage CLT floor panels as coupling elements for CLT shearwall stacks in the building floor plan. This approach is fundamentally different from traditional isolated shearwall stack design methods used in multistory light-framed wood buildings. The proposed method was illustrated through the seismic design of a 12-story CLT building located in Los Angeles, California, which was then subjected to the design equivalent lateral force to evaluate the conservativeness in the proposed simplified calculation.