Following his trade from the New York Rangers, Maciver made his Hartford Whalers debut on December 26, 1988, as he had no points in a 4–3 loss to the Pittsburgh Penguins. In his next game with Hartford two nights later on December 28, Maciver scored his first goal with his new club, scoring against Mario Gosselin of the Quebec Nordiques, and added two assists for his second career three point NHL game, in a 4–4 tie against the Nordiques. In 37 games with the Whalers, Maciver scored one goal and 23 points, helping the club reach the post-season. On April 9, 1989, Maciver appeared in his first career playoff game, as he was held to no points in a 4–3 loss to the Montreal Canadiens.