As the largest preserve in the nation's capital, Rock Creek Park would have its share of prominent visitors. Best remembered among them is Theodore Roosevelt.
"When our children were little, we were for several winters in Washington, and each Sunday afternoon the whole family spent in Rock Creek Park, which was then very real country indeed," Roosevelt recalled in his Autobiography. "I would drag one of the children's wagons; and when the very smallest pairs of feet grew tired of trudging bravely after us, or of racing on rapturous side trips after flowers and other treasures, the owners would clamber into the wagon." 
While in the White House I always tried to get a couple hours' exercise in the afternoons--sometimes tennis, more often riding, or else a rough cross-country walk, perhaps down Rock Creek... Often, especially in the winters and early springs, we would arrange for a point to point walk, not turning aside for anything--for instance, swimming Rock Creek or even the Potomac if it came in our way. Of course under such circumstances we had to arrange that our return to Washington should be when it was dark, so that our appearance would scandalize no one. On several occasions we thus swam Rock Creek in the early spring when the ice was floating thick upon it We liked Rock Creek for these walks because we could do so much scrambling and climbing along the cliffs Once I invited an entire class of officers who were attending lectures at the War College to come on one of these walks; I chose a route which gave us the hardest climbing along the rocks and the deepest crossings of the creek; and my army friends enjoyed it hugely--being the right sort, to a man. 
Another high official park user during Roosevelt's administration was Adm. George Dewey of Manila Bay fame. A cool man under fire, Admiral Dewey once suffered such fright in the park that he wrote Col. John Biddle, District engineer commissioner, about it:
There came very near being a vacancy in the Admiral's grade yesterday. I was driving in Rock Creek Park, near the Military Road, having just turned at that Road and started back, when a large tree, which I had passed a minute before, fell not a hundred feet in front of met directly across the road, breaking into three pieces. I think in ten seconds more I would have been under it! This causes me to mention to you that in my drives through the park I have noticed a number of trees along the banks, as well as some along the Military Road, leaning badly and looking as though they were liable to fall.
Capt. Jay J. Morrow, acting for Biddle, assured the admiral that dangerous trees would be removed. 
Woodrow Wilson enjoyed drives and walks in Rock Creek Park during his presidency. In September 1915 he was courting Edith Boiling Galt, who would become his second wife. His driver would take them to a point on Ross Drive, let them walk alone in the woods, and pick them up at a point further along the road. 
After World War I the Office of Public Buildings and Grounds undertook to remove numerous dead trees, mostly blighted chestnut. Hundreds were sold to private cutters for telephone and telegraph poles. President Wilson was disturbed. "[C]ouldn't you give the trees in Rock Creek Park a vacation?" he wrote Colonel Ridley in April 1920. "I have been distressed by the number I have seen cut down there." Ridley answered that the only trees being cut were already dead and that the work was being done ''as a necessary part of the park preservation" in accordance with a 1918 report by the Olmsted Brothers landscape architecture firm. 
Wilson was unpersuaded. "I do not profess to be a forester, but the great majority of trees that I have noticed laying prostrate in the park are certainly sound," he replied. "1 know a sound tree when I see it inside the bark. Moreover, in one part of the park a whole plantation of young pines...have been cut down and it made my heart ache to see it." Ridley sent this message to Superintendent Gillen with orders to cease cutting any more trees, large or small, dead or alive, until further notice. Gillen responded that the cut pines were outside the park boundary, and Ridley so informed the president. 
Wilson maintained his interest in the park after he left office in March 1921 and moved to a house on S Street. That June, upset about news of the forthcoming golf course construction, he wrote Colonel Sherrill:
Is it possible that it is true that a golf course is to be laid out in Rock Creek Park? I am loath to believe that such an unforgivable piece of vandalism is even in contemplation, and therefore beg leave to enter my earnest and emphatic protest. That park is the most beautiful thing in the United States, and to mar its natural beauty for the sake of a sport would be to do an irretrievable thing which subsequent criticism and regret would never repair.
Sherrill replied evasively, suggesting that the tract under consideration was suited to the purpose but claiming that no definite steps had been taken other than to determine the public's wishes in the matter. The golf course construction began that October, as planned. 
A memorial in Rock Creek Park honors another prominent park user of the period: Jules Jusserand, French ambassador to the United States from 1903 to 1925. Jusserand was close to Theodore Roosevelt and often accompanied the president on his romps through the park. Congress authorized the memorial in June 1935, the Fine Arts Commission approved Joseph Freedlander's design for a granite bench a year later, the Jusserand Memorial Committee raised the necessary funds, and President Franklin D. Roosevelt dedicated the completed memorial on November 7, 1936. Placement of the memorial in the park, overlooking Beach Drive and the creek a short distance south of Pierce Mill, worried Rock Creek's National Park Service managers at the time: they feared it would constitute a precedent for further memorial intrusions in the natural setting. But the Jusserand bench remained the sole commemorative feature in the park.