When the elites line up for the New York City Marathon on November 1, there will be a mix of former winners, Olympic medalists, and two of the top American marathoners in the country, Conner Mantz and Zouhair Talbi.

Looking to spoil the party will be Andreas Almgren, a 31-year-old Swedish runner who won the World Half Marathon Championships in September. This will be Almgren’s debut at the 26.2-mile distance. Despite his inexperience, he’s a legitimate threat for the podium.

Almgren has an unconventional background as a pro runner. He was working a full-time job as a data scientist just two years ago. He mostly trains alone and coaches himself. But he’s far from a competitive amateur. He’s sponsored by Nike and has set European records in the road 10K (26:45) and half marathon (58:06).

Although his strengths have been on the track and shorter road events, Almgren has leaned fully into marathon training this fall, logging more than 135 miles a week and tackling long runs over 24 miles.…