After admission to the Virginia bar the same year, Lankford began his legal practice in
Norfolk, Virginia. During the First World War, he served as an ensign in the aviation service of the
United States Navy. Returning to Norfolk, Lankford attempted to revitalize the
Republican party in
Tidewater Virginia. He ran for Congress in both 1920 to the Sixty-seventh Congress and in 1924 to the Sixty-ninth Congress, but lost. Lankford won election as a
Republican in 1928 (the first Republican elected in the district in three decades), and re-election, so he served in both the Seventy-first and Seventy-second Congresses (March 4, 1929 – March 3, 1933). He secured a new post office and courthouse for Norfolk. Because U.S. District Judge
D. Lawrence Groner ruled for the black plaintiffs in two voting rights cases, some thought that after President
Herbert Hoover (a fellow Republican) promoted Judge Groner to the
U.S. Court of Appeals for the District of Columbia Circuit, Lankford would receive the nomination as District Court judge for the Eastern District of Virginia, where his father-in-law had served. However, the 1930 elections only gave the Republicans a slim majority in the House, so Lankford's vote became crucial. Lankford worked for the nomination of his former campaign manager and Assistant U.S. Attorney,
Luther B. Way, to the district court vacancy. However, as the
Great Depression deepened, Virginia (following the lead of the
Byrd Organization) in 1932 held an at-large election for all Congressional districts, leading to a Democratic sweep, despite Lankford's having secured almost $2 million in construction contracts for federal buildings in Norfolk. When individual districts were again established in 1934,
Colgate Darden of Southampton County (who had been elected at-large to the Seventy-third Congress) was elected to the re-established 2nd congressional district. Lankford was a delegate to the Republican National Conventions in both 1932 and 1936. Following Lankford's at-large election loss, President Hoover appointed Lankford
Referee in Bankruptcy of the Norfolk division, United States District Court, Eastern District of Virginia. He served until his death, reporting to District Judge Way, whom he had sponsored. ==Death and legacy==