Craig A. Spencer, the New York City doctor who tested positive for Ebola on Thursday, has dedicated himself to dealing with medical emergencies in faraway places.  Just 33, Dr. Spencer has worked on projects in Rwanda, Burundi and the Democratic Republic of Congo. He returned this month from a trip to Guinea, where he worked with Doctors Without Borders, helping to treat Ebola patients.  At home, he is an attending physician at NewYork-Presbyterian Hospital/Columbia University Medical Center, about 20 blocks from the apartment in Hamilton Heights in Upper Manhattan that he shares with his fiancée, Morgan Dixon. The couple are scheduled to marry next fall in Detroit, according to an announcement posted online.  Neighbors said that they did not see much of Dr. Spencer and that he seemed to be working most of the time. But when they had encountered him — often in his hospital scrubs — he had been friendly and quick to offer a hand carrying groceries into the building, a six-story, brick-faced structure just off Broadway.  “He’s a nice guy, and kind of, wow,” a neighbor, John Reston, said upon hearing that Dr. Spencer had tested positive for the deadly disease. “He’s a nice guy, friendly, jovial. And I know he’s really dedicated to his work. That he’s with Doctors Without Borders says who he is.”  Mr. Reston said he learned of Dr. Spencer’s affiliation with Doctors Without Borders, the humanitarian aid organization, through Ms. Dixon when he bumped into her in an elevator while Dr. Spencer was in Guinea. Mr. Reston said he had not seen the doctor since his return, but had seen him having a beer with friends at Harlem Public, a tavern a couple of blocks up Broadway.  Another resident of Dr. Spencer’s building on West 147th Street, Ricardo Lawrence, said he was less worried about the disease’s spreading than for the doctor’s welfare. “I’m more concerned about him, especially because he went over there to help people,” Mr. Lawrence said, adding that he did not know him beyond exchanging greetings in the hallways.  “I think he works all the time,” Mr. Lawrence said. “There’s a group of us in the building who are close, but everyone who lives here works such weird hours, we’re all like ships passing in the night.”  Dr. Spencer grew up on a middle-class block of single-family homes in Grosse Pointe, Mich., where he attended Grosse Pointe North High School, recalled Lauren Smith, a former schoolmate.  Ms. Smith, a 31-year-old financial analyst, said Dr. Spencer was “the typical guy next door.” She said he was “friendly to everyone he could be friendly to,” but “there was nothing standout about him.”  Today Dr. Spencer’s résumé would indicate otherwise. After graduating from Wayne State University School of Medicine in Detroit, he earned a Master of Public Health degree at Columbia University’s Mailman School of Public Health, and he recently completed a fellowship in international emergency medicine at NewYork Presbyterian/Columbia. His profile on LinkedIn states that he is fluent in Chinese, French and Spanish. He studied Chinese at Henan University in China, which is where he met Ms. Dixon.  But judging by the online announcement of their wedding, scheduled for Sept. 5, he is not all work and no play: “Craig’s friends say he’s a goofball, incredibly gifted in both art, music and science, and a go-getter.”  Reporting was contributed by Kia Gregory, Rose Hackman, William K. Rashbaum and Tatiana Schlossberg.  A version of this article appears in print on October 24, 2014, on page A24 of the New York edition with the headline: Neighbors Say Patient Is Fast to Lend a Helping Hand. Order Reprints|Today's Paper|Subscribe
Dr. Craig Spencer, 33, traveled with Doctors Without Borders to Burundi, Congo and Rwanda before going to Guinea.